Journal of Double Star Observations - JDSO.org

Vol. 8 No. 2 April 1, 2012 

University of South Alabama 

Journal of Double Star Observations 

Journal of 

Double Star Observations 

Page 

VOLUME 8 NUMBER 2 April 1, 2012 

Inside this issue: 

Common Proper Motion Pairs in the LSPM-North Catalog 

Carlos E. López, Florencia Calandra, Martín Chalela, Cecilia López, Luis Pereyra, Emanuel Sillero, 

Measures and Relative Motions of Some Mostly F. G. W. Struve Doubles 

E. O. Wiley 

Observation Report for the Year 2009, Humacao University Observatory 

R. J. Muller, J.C. Cersosimo, D. Centeno, L. Rivera-Rivera, E. Franco, V. Maldonado, M. De Jesus, R.A. 

Rodriguez, A.J. Sosa, M. Rosario, M. Diaz 

CCD Measurements of Espin’s Neglected Double Stars: First in a Series 

Juan-Luis González Carballo 

Observations, Analysis, and Orbital Calculation of the Visual Double Star 

STTA 123 AB 

Nicholas J. Brashear, Angel J. Camama, Miles A. Drake, Miranda E. Smith, Jolyon M. Johnson, Dave 

Arnold, Rebecca Chamberlain 

73 

81 

92 

97 

122 

Orbital Elements for BU 741 AB, STF 333 AB, BU 920, and R 207 

Francisco Rica 

Astrometric Observation of Delta Cepheus 

Naomi Warren, Betsie Wilson, Chris Estrada, Kim Crisafi, Jackie King, Stephany Jones, Akash Salam, 

Glenn Warren, S. Jananne Collins, Russell Genet 

Astrometric Measurements of Selected Visual Double Stars 

Jonathan Boyd, Anthony Brokaw, Jackie Deventer, Monica Garcia’, Mario Gastelum, Yvelisse Guerrero, 

Joy Hallett, Kelli Heape, Margarita Ibarra, Richard Langston, Dawn Maddux, Jack Moreland, Randall 

Mozzillo, Jason Overholts, Kevin Perez, Valorie Randle, Samantha Savard, Mike Stewart, Lajeana West, 

Angela McClure, Douglas Walker 

Measurements of Beta Lyrae at the Pine Mountain Observatory Summer 

Workshop 2011 

Joseph Carro, Rebecca Chamberlain, Marisa Schuler, Timothy Varney, Robert Ewing, Russell Genet 

Visual Astrometry Observations of the Binary Star Beta Lyrae 

S. Jananne Collins, Kyle M. Berlin, Clare E. Cardoza, Chris D. Jordano, Tatum A. Waymire, Doug P. 153 

Shore, John Baxter, Robert Johnson, Joseph Carro, Russell M. Genet 

Observations of the Binary Star Nu Draco 

Jordan Fluitt, Everett Heath, Bobby Johnson, Grayson Ortiz, Hollie Charles, Reed Estrada, Russell Genet 157 

127 

140 

142 

150 

Three New Common Proper Motion Binaries in Cetus, Pisces and Leo Minor 

Constellations 

Francisco Rica Romero 

Study of a New CPM Pair 2Mass 01300483-2705191 

Israel Tejera Falcón 

160 

168

Vol. 8 No. 2 April 1, 2012 


Page 73 

Common Proper Motion Pairs 

in the LSPM-North Catalog 

Carlos E. López 

Observatorio Astronómico Félix Aguilar 

Universidad Nacional de San Juan, Argentina 

celopez@speedy.com.ar 

Florencia Calandra, Martín Chalela, Cecilia López, Luis Pereyra, 

Emanuel Sillero, and Matías Vera 

Departamento de Geofísica y Astronomía 

Universidad Nacional de San Juan, Argentina 

Abstract: We report the identification of 96 Common Proper Motion Pairs (CPMP) detected 

among the stars listed in the Lepine – Shara Proper Motion (LSPM)-North Catalogue. 

The separations of these pairs range from about 5 seconds of arc up to almost 170 

seconds of arc. 

Introduction 

For the past three years, we have been conducting 

a data mining search in order to provide improved 

coordinates, separations, position angles and 

proper motions for some of the double stars listed in 

the Washington Double Star (WDS) Catalog. Attention 

has been especially focused on LDS systems for 

which we identified some differences between the 

values quoted in various astrometric databases and 

those included in the WDS. We have also isolated 

those CPMP that - prima facie - were not found in 

the WDS. 

In general the project serves a twofold purpose. 

On the one hand, it is aimed at searching for additional 

astrometric information about double stars 

and identifying new pairs. On the other hand, it 

seeks to introduce undergraduate students to the use 

of large databases through the tools proposed in 

some of the Virtual Observatory initiatives. 

The databases we are currently searching include, 

among others, SuperCosmos (Hambly et al. 

2001), UCAC3 (Zacharias et al. 2010), USNO B1.0 

(Monet et al. 2003), SPM4 (Girard et al. 2011) and 

LSPM-North (Lepine and Shara, 2005). 

Search and Results 

In order to identify potential CPMP among the 

LSPM-North stars, we have followed a very simple 

process, namely, the proper motion comparison of 

each of the stars listed in the database (see López 

2008 for preliminary results). This approach has 

proven to be very useful as it has allowed many authors 

to identify hundreds of new, previously unreported 

CPMP that are now included in the WDS. As 

an example, we can mention the searches performed 

by Greaves (2004, 2005), Caballero (2010), and Caballero 

et al. (2010). Another important search was 

that made by Halbwachs (1986) using the data of the 

AGK2/3. This search involved the development of 

specific criteria to decide when a pair of stars could 

be referred to as a CPMP, which led to the identification 

of a number of new pairs. 

The first step in our Data Mining was to compile 

a preliminary list of CPMP, which was then crossidentified 

with the WDS we downloaded on July 27, 

2011. As we found that many of the pairs in our list 

were already included in the WDS, all the stars in

Vol. 8 No. 2 April 1, 2012 


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common were deleted. We also deleted from our preliminary 

list some very close pairs which could not be 

confirmed by using other astrometric and nonastrometric 

compilations (such as 2MASS). The components 

of many of these very close pairs, although 

listed as two individual stars with different LSPM 

numbers in the LSPM-North Catalog, are identified 

as a single star in most of the databases checked. 

These pairs have been set apart for later analysis. 

The next step in the process was to analyze which 

of the systems have real chances of being physical 

pairs and which ones should be regarded as optical 

systems. This problem has been addressed by Poveda 

et al. (1982), and Halbwachs (1986), among many others 

(see Benavides et al. 2010 for a summary of different 

methods). For our purposes, we adopted 

Halbwachs’ (1986). Finally, in order to double check 

the nature of the CPMP found, we relied on the tools 

provided by Aladin to superimpose POSS1 and 

POSS2 images, as well as on some of the databases 

currently being used in our study. Having followed all 

these steps, we completed the identification of the 96 

objects reported in this note. 

Our results are presented in Table 1. With the 

exception of the last two columns, the data have been 

directly taken from the LSPM-North Catalog. RA and 

Dec are in degrees and proper motions in seconds of 

arc per year. Position angles and separations (epoch 

2000.0) were computed from the corresponding RA 

and Dec given. 

To our best knowledge, the CPMP herein reported 

are not included in the Washington Double Star Catalog 

(review made on September 28, 2011). 

Acknowledgements 

This research has made use of the Washington 

Double Star Catalog maintained at the U.S. Naval 

Observatory and the Aladin facilities. 

This publication makes use of data products from 

the Two Micron All Sky Survey, which is a joint project 

of the University of Massachusetts and the Infrared 

Processing and Analysis Center/California Institute 

of Technology, funded by the National Aeronautics 

and Space Administration and the National Science 

Foundation. 

References: 

Benavides, R., Rica, F., Reina, E., et al., 2010, JDSO, 

6, 30. 

Caballero, R., 2010, JDSO, 6, 160. 

Caballero, R., Collado-Iglesias, B., Pozuelo-González, 

S., et al., 2010, JDSO, 6, 206. 

Greaves, J., 2004, MNRAS 355, 585. 

Greaves, J., 2005, JDSO, 1, 41. 

Halbwachs, J. L., 1986, A&ASS 66, 131. 

Hambly, N., MacGillivray, H., Read, M., et al., 2001, 

MNRAS 326, 1279. 

Lepine, S, and Shara, M., 2005, AJ 129, 1483 (Online 

VizieR Catalogue I/298). 

López, C. E., 2008, RMxAA (Serie de Conferencias) 

34, 123. 

Monet D.G., Levine S.E., Casian B., et al., 2003, AJ, 

125, 984 (Online VizieR Catalogue I/284). 

Poveda, A., Allen, C., and Parrao, L., 1982, ApJ, 258, 

589. 

Zacharias, N., Finch C., Girard T., et al., 2010, AJ, 

139, 2184 (Online VizieR Catalogue I/315). 

Carlos E. López teaches an introductory course of astronomy for undergraduate 

students at the National University of San Juan, Argentina. 

Florencia Calandra, Martín Chalela, Cecilia López, Luis Pereyra, Emanuel 

Sillero and Matías Vera are astronomy undergraduate students at the 

Universidad Nacional de San Juan, Argentina.

Vol. 8 No. 2 April 1, 2012 


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Table 1: Identification and Astrometric Data 

LSPM 2MASS RA Dec pmRA pmDec Ve PA Sep 

A 0008+1633 2.223711 16.565207 0.158 -0.119 20.07 325 13.8 

B 0008+1634 2.221412 16.568356 0.158 -0.119 20.47 

A 0111+4248 01115514+4248024 17.979815 42.800587 0.126 -0.170 11.23 215 115.1 

B 0111+4246 01114909+4246283 17.954638 42.774498 0.128 -0.182 15.00 

A 0122+2758 01221631+2758005 20.568094 27.966770 0.141 -0.081 19.17 108 5.0 

B 0122+2757 01221667+2757590 20.569574 27.966341 0.141 -0.081 19.30 

A 0201+0218 02011509+0218257 30.312868 2.307160 0.217 -0.033 17.44 151 63.8 

B 0201+0217 02011713+0217296 30.321337 2.291575 0.217 -0.033 18.87 

A 0316+0618 03165886+0618086 49.245281 6.302413 0.181 -0.122 19.50 210 75.9 

B 0316+0617 03165635+0617027 49.234798 6.284081 0.181 -0.122 19.74 

A 0323+1506 03232730+1506520 50.863747 15.114393 -0.061 -0.152 14.73 185 67.9 

B 0323+1505 03232686+1505444 50.861935 15.095627 -0.061 -0.152 16.13 

A 0329+7556 03292257+7556596 52.344208 75.949875 0.160 -0.129 17.37 302 36.9 

B 0329+7557 03291399+7557193 52.308468 75.955353 0.160 -0.129 19.79 

A 0331+0749 03312821+0749469 52.867573 7.829704 0.163 -0.039 12.42 355 17.2 

B 0331+0750 03312812+0750040 52.867180 7.834460 0.163 -0.039 18.72 

A 0339+5632 03391532+5632058 54.813854 56.534962 0.192 -0.058 15.20 166 24.3 

B 0339+5631 03391602+5631422 54.816757 56.528400 0.192 -0.058 19.46 

A 0433+0013 04331784+0013595 68.324326 0.233273 -0.060 -0.151 11.43 41 18.9 

B 0433+0014 04331867+0014140 68.327789 0.237227 -0.062 -0.149 16.85 

A 0449+4048 04493734+4048017 72.405609 40.800407 0.027 -0.213 14.02 205 6.5 

B 0449+4047 04493709+4047557 72.404587 40.798763 0.027 -0.213 15.04 

A 0509+1038 05094259+1038438 77.427460 10.645508 -0.036 -0.177 15.15 317 45.4 

B 0509+1039 05094048+1039170 77.418686 10.654724 -0.036 -0.177 18.99 

A 0524+0315 05244976+0315154 81.207329 3.254313 0.271 -0.127 10.71 246 48.2 

B 0524+0314 05244682+0314557 81.195084 3.248834 0.253 -0.120 14.94 

A 0535+0824 05351532+0824193 83.813843 8.405370 0.141 -0.067 11.14 349 140.0 

B 0535+0826 05351350+0826367 83.806290 8.443538 0.141 -0.062 17.20 

A 0546+1306 05461292+1306098 86.553902 13.102634 0.085 -0.146 12.03 170 34.2 

B 0546+1305 86.555527 13.093266 0.085 -0.146 18.32 

A 0546+1116 05461726+1116466 86.571915 11.279618 -0.124 -0.155 16.50 207 53.8 

B 0546+1115 05461559+1115587 86.564980 11.266311 -0.124 -0.155 18.21 

A 0550+0939 05501174+0939492 87.548943 9.663702 0.258 0.235 16.01 317 16.2 

B 0550+0940 05501099+0940011 87.545845 9.667006 0.258 0.235 17.75 

A 0551+5051 05515028+5051566 87.959549 50.865734 -0.127 -0.084 10.34 336 6.2 

B 0551+5052 05515002+5052022 87.958458 50.867302 -0.127 -0.084 99.90 

Table continues on next page.

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Table 1 (continued): Identification and Astrometric Data 


A 0610+2802 06102564+2802236 92.606796 28.039850 -0.100 -0.143 10.80 171 161.0 

B 0610+2759 06102756+2759447 92.614799 27.995678 -0.097 -0.144 13.53 

A 0610+4439 06104398+4439498 92.683350 44.663815 0.193 -0.143 16.73 39 142.0 

B 0610+4441 06105244+4441395 92.718620 44.694263 0.179 -0.140 17.93 

A 0625+1634 06253267+1634050 96.386032 16.567974 -0.203 -0.156 15.83 116 52.7 

B 0625+1633 96.399773 16.561554 -0.203 -0.156 18.23 

A 0628+2829 06282826+2829230 97.117722 28.489660 -0.115 -0.152 16.03 148 100.2 

B 0628+2827 06283227+2827578 97.134407 28.465990 -0.115 -0.152 17.59 

A 0649+2942 06495322+2942038 102.471741 29.701172 -0.028 0.189 14.13 182 34.2 

B 0649+2941 06495313+2941296 102.471397 29.691668 -0.028 0.189 16.08 

A 0653+3026 06531618+3026039 103.317375 30.434402 -0.132 -0.087 15.93 187 7.3 

B 0653+3025 06531611+3025567 103.317078 30.432396 -0.132 -0.087 16.29 

A 0705+4129 07053254+4129100 106.385712 41.486076 0.138 -0.094 14.05 135 87.2 

B 0705+4128 07053804+4128084 106.408615 41.468975 0.138 -0.094 14.47 

A 0720+3657 07203806+3657475 110.158623 36.963203 -0.015 -0.160 12.28 5 12.6 

B 0720+3658 07203816+3658000 110.159035 36.966675 -0.015 -0.160 15.44 

A 0727+4228 07275077+4228198 111.961609 42.472118 0.060 -0.155 16.33 173 32.1 

B 0727+4227 07275114+4227480 111.963135 42.463280 0.060 -0.155 18.17 

A 0749+2435 07495456+2435131 117.477325 24.586933 -0.014 -0.178 11.89 342 96.9 

B 0749+2436 07495237+2436454 117.468231 24.612555 -0.014 -0.178 15.26 

A 0750+0429 07505800+0429003 117.741684 4.483431 -0.165 -0.052 16.50 189 5.0 

B 0750+0428 07505795+0428553 117.741463 4.482053 -0.165 -0.052 99.90 

A 0802+1326 08022370+1326239 120.598778 13.439995 -0.102 -0.141 14.58 142 73.3 

B 0802+1325 08022677+1325259 120.611588 13.423889 -0.102 -0.141 19.54 

A 0802+2851 08024181+2851062 120.674217 28.851751 -0.135 -0.154 14.90 149 87.4 

B 0802+2849 08024523+2849513 120.688492 28.830944 -0.135 -0.154 20.50 

A 0802+0019 08025006+0019091 120.708595 0.319218 -0.119 -0.141 13.37 115 78.7 

B 0802+0018 08025481+0018359 120.728416 0.309999 -0.119 -0.141 16.83 

A 0813+1527 08133754+1527150 123.406326 15.454165 -0.152 -0.017 12.16 296 148.0 

B 0813+1528 08132832+1528193 123.367905 15.472042 -0.155 -0.017 18.44 

A 0822+1145 08223314+1145055 125.638107 11.751541 -0.205 -0.045 12.92 148 7.6 

B 0822+1144 08223341+1144590 125.639244 11.749749 -0.205 -0.045 99.90 

A 0840+6144 08400461+6144444 130.019257 61.745708 -0.075 -0.228 18.36 75 84.7 

B 0840+6145 08401613+6145065 130.067261 61.751823 -0.075 -0.228 19.07 

A 0855+3732 08555987+3732108 133.999359 37.536369 -0.174 0.038 14.30 125 80.2 

B 0856+3731 08560536+3731242 134.022247 37.523430 -0.174 0.038 17.04 


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A 0900+0643 09005207+0643315 135.216965 6.725435 -0.154 0.053 13.91 199 44.7 

B 0900+0642 09005111+0642491 135.212997 6.713663 -0.154 0.053 16.71 

A 0902+0600 09025127+0600280 135.713638 6.007769 -0.149 0.111 9.80 16 105.6 

B 0902+0602 09025320+0602095 135.721680 6.035985 -0.144 0.107 14.71 

A 0906+7226 09065614+7226093 136.734039 72.435852 0.175 -0.465 16.03 74 24.5 

B 0907+7226 09070133+7226162 136.755661 72.437744 0.175 -0.465 17.93 

A 0929+0350 09290981+0350079 142.290894 3.835543 -0.119 -0.167 15.83 228 37.8 

B 0929+0349 09290794+0349424 142.283096 3.828474 -0.119 -0.167 16.13 

A 1100+0100 11005917+0100076 165.246567 1.002118 -0.320 -0.084 13.20 150 41.5 

B 1101+0059 11010055+0059316 165.252304 0.992129 -0.320 -0.084 19.25 

A 1102+2353 11020198+2353085 165.508163 23.885649 -0.157 -0.100 14.55 119 97.7 

B 1102+2352 11020821+2352211 165.534134 23.872486 -0.157 -0.100 16.95 

A 1118+6048 11182861+6048015 169.619308 60.800423 0.137 -0.058 17.78 184 23.8 

B 1118+6047 169.618286 60.793842 0.137 -0.058 20.42 

A 1135+3109 11351194+3109267 173.799683 31.157419 -0.161 -0.046 16.63 351 131.3 

B 1135+3111 11351029+3111363 173.792801 31.193417 -0.157 -0.042 18.28 

A 1147+1640 11471686+1640074 176.820114 16.668682 -0.294 -0.090 16.57 154 8.4 

B 1147+1639 11471712+1639599 176.821182 16.666594 -0.294 -0.090 16.63 

A 1148+0018 11485156+0018038 177.214844 0.301060 -0.176 -0.003 14.82 155 4.6 

B 1148+0017 11485169+0017596 177.215378 0.299896 -0.176 -0.003 99.90 

A 1149+4022 11493844+4022063 177.410156 40.368320 -0.077 -0.260 15.38 130 21.3 

B 1149+4021 177.416107 40.364502 -0.077 -0.260 21.71 

A 1206+1218 12060212+1218190 181.508850 12.305192 -0.006 -0.182 13.29 269 38.1 

B 1205+1218 12055952+1218187 181.498032 12.305099 -0.006 -0.182 16.57 

A 1209+2818 12094182+2818088 182.424179 28.302420 -0.168 -0.055 18.83 194 13.4 

B 1209+2817 12094158+2817557 182.423172 28.298798 -0.168 -0.055 19.36 

A 1223+0625 12234348+0625103 185.931183 6.419538 -0.183 -0.029 14.06 159 23.4 

B 1223+0624 12234403+0624483 185.933487 6.413444 -0.183 -0.029 18.52 

A 1233+0824 188.306030 8.401087 -0.172 0.132 18.46 147 111.0 

B 1233+0822 188.322800 8.375109 -0.172 0.132 19.34 

A 1235+4402 12355441+4402497 188.976837 44.047047 0.188 -0.266 13.00 299 36.9 

B 1235+4403 188.964417 44.052071 0.188 -0.266 19.60 

A 1236+1457 12361340+1457171 189.055771 14.954708 -0.159 -0.118 16.20 14 80.5 

B 1236+1458 12361476+1458352 189.061432 14.976391 -0.159 -0.118 18.25 

A 1300+7548 13000780+7548217 195.032379 75.806023 -0.212 -0.022 12.42 188 25.4 

B 1300+7547 13000680+7547565 195.028183 75.799042 -0.212 -0.022 20.59 


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A 1310+3252 13102143+3252584 197.589218 32.882919 -0.173 0.011 14.55 360 66.5 

B 1310+3254 13102143+3254049 197.589188 32.901382 -0.173 0.011 17.40 

A 1311+1106 13114181+1106247 197.924225 11.106891 -0.111 -0.130 12.89 253 146.8 

B 1311+1105 13113230+1105406 197.884598 11.094645 -0.115 -0.122 17.83 

A 1324+4619 201.216278 46.332203 0.065 -0.156 18.82 304 8.2 

B 1324+4620 201.213547 46.333462 0.065 -0.156 19.88 

A 1352+2806 13520228+2806488 208.009491 28.113567 -0.188 0.054 14.53 1 11.4 

B 1352+2807 13520229+2807001 208.009537 28.116730 -0.188 0.054 14.62 

A 1358+3842 13584494+3842328 209.687134 38.709114 -0.201 -0.021 14.50 348 39.8 

B 1358+3843 13584423+3843117 209.684204 38.719929 -0.201 -0.021 18.17 

A 1359+0632 13590955+0632003 209.789810 6.533382 -0.143 0.114 9.95 254 5.6 

B 1359+0631 13590918+0631586 209.788300 6.532964 -0.140 0.112 99.90 

A 1424+1804 14243602+1804140 216.150085 18.070560 -0.149 -0.070 16.48 225 33.3 

B 1424+1803 14243437+1803503 216.143234 18.063992 -0.149 -0.070 18.53 

A 1433+5101 14335998+5101076 218.499924 51.018799 0.094 -0.120 16.33 263 71.6 

B 1433+5100 218.468552 51.016392 0.094 -0.120 19.59 

A 1504+1422 15043948+1422115 226.164474 14.369870 -0.259 -0.003 13.37 231 26.4 

B 1504+1421 15043807+1421549 226.158569 14.365274 -0.259 -0.003 20.70 

A 1516+6054 15164985+6054374 229.207733 60.910431 0.048 -0.440 13.25 178 92.1 

B 1516+6053 15165035+6053054 229.209808 60.884872 0.048 -0.440 20.03 

A 1623+2438 16233762+2438152 245.906784 24.637602 -0.098 -0.145 10.54 169 135.3 

B 1623+2436 245.914368 24.600647 -0.103 -0.150 19.57 

A 1646+0347 16462350+0347583 251.597961 3.799562 -0.172 -0.067 15.39 340 11.7 

B 1646+0348 16462324+0348093 251.596848 3.802606 -0.172 -0.067 19.06 

A 1709+1730 17090307+1730569 257.262756 17.515816 -0.154 0.006 16.20 358 5.0 

B 1709+1731 17090305+1731019 257.262695 17.517214 -0.154 0.006 99.90 

A 1712+0132 17124318+0132044 258.179993 1.534555 -0.152 0.023 13.59 145 22.4 

B 1712+0131 17124404+0131460 258.183533 1.529444 -0.152 0.023 15.42 

A 1729+0746 17295145+0746570 262.464386 7.782518 -0.022 -0.171 12.07 306 6.9 

B 1729+0747 17295107+0747010 262.462830 7.783637 -0.022 -0.171 99.90 

A 1734+4858 17343968+4858049 263.665314 48.968109 -0.054 0.155 14.38 145 55.4 

B 1734+4857 17344290+4857195 263.678741 48.955494 -0.054 0.155 14.43 

A 1738+3939 17380857+3939154 264.535706 39.654312 -0.055 0.150 16.66 157 21.2 

B 1738+3938 17380927+3938558 264.538635 39.648884 -0.055 0.150 19.94 

A 1823+0403 18231983+0403164 275.832642 4.054560 -0.170 0.009 16.52 9 79.0 

B 1823+0404 18232070+0404343 275.836243 4.076203 -0.170 0.009 17.57 


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A 1823+2022 18235962+2022487 275.998413 20.380228 -0.166 -0.078 18.13 51 87.7 

B 1824+2023 18240446+2023441 276.018585 20.395603 -0.166 -0.078 18.73 

A 1847+4629 18473898+4629083 281.912445 46.485729 -0.012 0.166 15.56 187 15.1 

B 1847+4628 281.911713 46.481560 -0.012 0.166 20.45 

A 1932+1723 19325604+1723567 293.233582 17.399023 0.172 -0.198 15.20 160 150.6 

B 1932+1721 19325969+1721355 293.248779 17.359795 0.165 -0.210 18.18 

A 1933+6526 19330164+6526519 293.256775 65.447746 -0.156 -0.103 18.48 233 17.5 

B 1932+6526 19325939+6526414 293.247406 65.444839 -0.156 -0.103 18.58 

A 2059+4224 20594623+4224537 314.942627 42.414928 0.169 0.024 15.25 347 38.2 

B 2059+4225 20594548+4225310 314.939484 42.425278 0.169 0.024 19.95 

A 2106+5924 21061829+5924018 316.576233 59.400482 -0.110 -0.119 10.91 332 120.3 

B 2106+5925 21061099+5925483 316.545776 59.430096 -0.108 -0.115 16.19 

A 2131+4700 21310438+4700581 322.768341 47.016220 0.209 0.255 12.66 346 9.2 

B 2131+4701 21310416+4701071 322.767456 47.018715 0.209 0.255 99.90 

A 2133+5001 21330337+5001032 323.264099 50.017563 -0.168 -0.037 12.83 326 66.2 

B 2132+5001 21325948+5001577 323.247894 50.032719 -0.168 -0.037 17.47 

A 2146+1550 21463230+1550389 326.634827 15.844217 0.309 0.116 16.16 324 154.9 

B 2146+1552 21462606+1552449 326.608826 15.879240 0.304 0.121 16.56 

A 2203+4358 22033629+4358592 330.901184 43.983105 0.145 0.050 15.33 86 13.3 

B 2203+4359 22033752+4359000 330.906311 43.983345 0.145 0.050 19.20 

A 2211+1819 22114389+1819141 332.932892 18.320580 -0.068 -0.135 13.58 171 17.3 

B 2211+1818 22114408+1818570 332.933685 18.315830 -0.068 -0.135 15.00 

A 2217+4242 22172686+4242141 334.362030 42.703918 0.188 -0.017 14.56 173 19.8 

B 2217+4241 334.362915 42.698444 0.188 -0.017 19.96 

A 2222+2309 22223361+2309496 335.640106 23.163803 -0.167 -0.122 13.55 204 119.0 

B 2222+2308 22223008+2308010 335.625397 23.133631 -0.182 -0.111 16.50 

A 2248+2723 22481493+2723024 342.062347 27.383993 0.171 -0.017 14.90 115 6.6 

B 2248+2722 22481537+2722596 342.064209 27.383219 0.171 -0.017 99.90 

A 2255+3325 22550566+3325060 343.773682 33.418304 0.153 -0.073 16.23 204 9.9 

B 2255+3324 343.772369 33.415791 0.153 -0.073 99.90 

A 2256+5919 22561349+5919087 344.056244 59.319046 0.124 0.107 11.50 352 152.8 

B 2256+5921 22561075+5921399 344.044769 59.361080 0.125 0.113 18.20 

A 2312+2701 23124700+2701045 348.195831 27.017931 0.169 -0.024 11.61 109 53.5 

B 2312+2700 23125076+2700468 348.211578 27.013012 0.161 -0.025 19.30 

A 2326+1952 23261725+1952155 351.571899 19.870993 -0.134 -0.104 18.62 181 31.9 

B 2326+1951 23261721+1951436 351.571777 19.862135 -0.134 -0.104 20.56 

Table concludes on next page.

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Table 1 (conclusion): Identification and Astrometric Data 


A 2330+3330 23305581+3330582 352.732513 33.516159 -0.125 -0.090 13.73 359 41.4 

B 2330+3331 352.732269 33.527664 -0.125 -0.090 99.90 

A 2335+6750 23353800+6750016 353.908508 67.833778 0.139 0.063 10.56 331 133.9 

B 2335+6751 23352650+6751585 353.860474 67.866264 0.141 0.060 17.89 

A 2337+2127 23374838+2127412 354.451599 21.461403 -0.023 -0.213 17.93 1 19.6 

B 2337+2128 354.451752 21.466843 -0.023 -0.213 19.92 

A 2343+1345 23431810+1345430 355.825378 13.761855 -0.029 -0.170 17.38 119 160.1 

B 2343+1344 23432774+1344263 355.865570 13.740560 -0.027 -0.170 17.93 

A 2349+1108 23491766+1108514 357.323578 11.147657 0.084 -0.154 14.50 46 17.0 

B 2349+1109 23491849+1109032 357.327026 11.150946 0.084 -0.154 18.89 

A 2352+4625 23521505+4625520 358.062805 46.431141 0.165 0.033 16.98 347 56.4 

B 2352+4626 23521383+4626470 358.057739 46.446415 0.165 0.033 17.58

Vol. 8 No. 2 April 1, 2012 


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Measures and Relative Motions of Some Mostly 

F. G. W. Struve Doubles 

E. O. Wiley 

Remote Astronomical Society Observatory 

Mayhill, NM 

Mailing address: 2503 Atchison Ave. 

Lawrence KS 66047 

edwiley@sunflower.com 

Abstract: Measures of 59 pairs of double stars with long observational histories using 

“lucky imaging” techniques are reported. Relative motions of 59 pairs are investigated using 

histories of observation, scatter plots of relative motion, ordinary least-squares (OLS) and 

total proper motion analyses performed in “R,” an open source programming language. A 

scatter plot of the coefficient of determinations derived from the OLS y|epoch and OLS 

x|epoch clearly separates common proper motion pairs from optical pairs and what are 

termed “long-period binary candidates.” Differences in proper motion separate optical pairs 

from long-term binary candidates. An Appendix is provided that details how to use known 

rectilinear pairs as calibration pairs for the program REDUC. 

Introduction 

In Wiley (2010) I presented a protocol for estimating 

rectilinear elements of optical doubles and 

commented on the use of ordinary least-squares 

(OLS) analysis for exploring the nature of common 

proper motion and binary pairs. In this paper I expand 

on that investigation by measuring and analyzing 

a number of mainly F. G. W. Struve (STF) doubles 

where one or both of the pairs have a measurable 

proper motion, defined as a proper motion that 

exceeds errors. The exercise is largely an inductive 

data-exploration exercise to see if there are some 

relatively simple and approachable analyses available 

to amateur researchers that would separate optical 

pairs from physical pairs. Fifty-four 

“knowns” (proper motions reported for both stars) 

were selected from the WDS catalog. I included four 

“unknowns” (proper motion high in one star but unknown 

in the other) to see if the techniques developed 

during this inductive exercise would successfully 

discriminate them. To add value to the exercise 

I picked my “knowns” in the WDS from pairs with no 

indication in the WDS Notes column that they have 

been characterized as optical or physical. 

Methods 

Many of the pairs measured herein have separations 

of 3” - 6” and this necessitated using a form of 

“lucky imaging” with a Takahashi Mewlon 0.3 meter 

telescope at the GRAS observatories in Mayhill, New 

Mexico. I typically took 20 - 50 short exposures (0.25 

- 1 second) and picked only those where there was a 

clear separation between the pairs. 

Theta and rho were measured using REDUC 

(Losse, 2010 et seq.) which has a distinct advantage 

when working with short exposures as one does not 

have to reduce the plate. In some cases individual 

images were eliminated due to poor quality 

(“unlucky” images) and in other cases images were 

stacked to improve signal-to-noise ratio (see Table 1). 

REDUC requires at least one calibration pair to determine 

camera orientation and plate scale. I used 

two relatively wide optical pairs with excellent rectilinear 

elements (02157+6740 ENG 10 and 

23280+2335 STTA246AB). A protocol for reducing

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rectilinear elements to theta and rho for a given date 

for a calibration pair is detailed in Appendix A. 

Astrophysical data were gathered using Aladin in 

conjunction with various catalogs. Proper motions 

were taken from the Washington Double Star Catalog 

(Mason et al., 2001-2011) and checked against the 

Tycho 2 (I/259; Hog et al., 2000), Hipparchos (I/239; 

ESA, 1995), the All-sky Compiled (I/280B; Kharchenko 

and Roeser, 2009) and PPMXL catalogs (I/317; 

Roeser et al. 2010) available at the CDS (Bonnarel et 

al., 2000). 

The histories of measures for each pair were requested 

from the U. S. Naval Observatory (Mason, 

2006). Since this is a proof-of-concept paper, most 

STF pairs were chosen based on pairs with moderate 

to large proper motions where each pair was had either 

(1) similar proper motions (≤ 10 mas/year difference 

in both RA and Dec) and presumed to be physically 

associated or (2) dissimilar proper motions (≥ 11 

mas/year difference in RA and Dec) presumed to be 

optical pairs. Four pairs were included that had one 

but not both members with proper motion data 

greater than 25 mas/year; these act as unknowns. 

Specific steps in the analysis are listed below. 

1. Convert theta and rho measures to Cartesian 

(x,y) coordinates in an Excel ® spread sheet (see Wiley, 

2010). 

2. Using the plotting functions in Excel ® , examine 

the relative motions in Cartesian space. Examination 

is facilitated by using the line function to connect observations 

by epoch of observation and a rough idea of 

the relationship between x- and y-values can be investigated 

by line fitting using the trend line function. 

(The trend line function can return an OLS solution, 

but more formal analyses should be performed.) Of 

particular interest are indications of no relative motion 

(relative position of the secondary clustered 

around one position), linear motion (relative motion 

follows a straight line, forming a time series of historically 

ordered measures) and curvilinear motion 

(some indication of orbital motion). An OLS y|x solution 

was calculated for each pair using the “lm” functions 

of the R programming language (Ihaka and 

Gentleman, 1996). This “lm” function is simply a call 

to R to perform linear regression on the variables. I 

note, based on comments by Dr. Richard Branham 

(pers. comm.), that Total Least Squares (TLS) may be 

the more appropriate technique since both x- and y- 

values are subject to errors (e.g. Branham, 2001). I 

plan to explore TLS techniques in future studies as a 

TLS package is available in R. 

3. Perform two ordinary least squares (OLS) 

analyses, again using “R,” on each pair using epoch of 

observation as the independent variable and x- and y- 

values as dependent variables. Test the null hypothesis 

that slopes of each analysis are statistically no 

different than zero (flat slope) and harvest the coefficients 

of variation (R 2 ) from each analysis. Such 

analyses can also be performed using the more formal 

“Regression” function in the Excel ® data analysis tool 

pack. Since epoch of observation can be taken as 

“without error,” OLS, rather than TLS, is the appropriate 

regression analysis in these cases. 

4. In Excel ® , visualize relationship between the 

coefficients of determination of each analysis performed 

in 3 above, with R 2 of the OLS x|epoch as the 

x-axis and the R 2 of the OLS y|epoch as the y-axis of 

a scatter plot. 

5. The average relative motion in arc seconds per 

year along the x-axis and y-axis is the slope function 

of the regression equations derived from the OLS 

x|epoch and OLS y|Epoch unless there are obvious 

changes in velocity signaled by concave relative motion. 

For example, the equations for the optical pair 

00546+3910STF 72 (rounded for simplicity) are: 

X = 0.02225Epoch – 41.96 

Y = -0.00677Epoch + 38.82 

The motions are 0.0223 ± 0.001 arcsecond/year 

along the x-axis and -0.007 ± 0.001 arcseconds/year 

along the y-axis. Using the Pythagorean formula, calculate 

the average total relative motion. This yields 

total motion in arc seconds. For example, 

00546+3910STF 72: 

2 2 

RM = a + b 

RM 

tot 

tot 

( ) 

2 2 

= 0.02225 + ( − 0.0067) = 0.02324 a.s./yr 

6. Convert the total motion to average motion/ 

year in milliseconds (mas/year) by multiplying by 

1000 to make the value comparable to those in the 

WDS, which is in mas/year. 

0.02324 a.s./yr * 1000 = 23.24 mas/year 

7. To check this calculation against catalog proper

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motion values, calculate average relative motion using 

catalog motions in right ascension and declination 

of x- and y-values for the pair and use the distance 

formula to determine total relative motion. 

From WDS, Primary: pm RA = -020 mas/year p, 

Dec = -020 mas/year 

From WDS, Secondary: pm RA -001 mas/year p, 

Dec = 014 mas/year 

2 2 

relative motion = ( −20 −( − 1)) + ( −20 −( −14)) 

= 19.92 mas/yr 

In this particular case, relative motions as shown 

by analysis of theta and rho in Cartesian space agree 

fairly well with published catalog values. Large differences 

would indicate that either the relative motion 

values or the catalog values are not accurate (or 

both). 

8. Compute the ratio of relative motion to the total 

motion of the primary. To compute total motion of 

the primate use the Pythagorean formula and the 

pmRA and pmDec of the primary For example, 

00502+1150STF 63AB. pmRA = +43 mas/yr, pm Dec 

= -54 mas/yr (WDS): 

PM 

tot 

2 2 

= a + b 

2 2 

PM tot = ( + 43) + ( − 54) = 69.03 mas/yr 

Ratio = RMtot / PMtot = (1.5612 mas/yr) / (69.03 mas/yr) = 2.262 

A system may exhibit a small relative motion 

simply because both components have small proper 

motions, so caution is in order when interpreting the 

result. 

Results 

Measures for 59 pairs are reported in Table 1, 

including measures for the calibration pair 

02152+6740ENG 10. Table 2 shows the results of 

three rounds of OLS analysis (OLS y|x, OLS x|epoch 

and OLS y|epoch). These results are reported as a 

single value, the coefficient of determination (R 2 ) annotated 

by the probability that the slope of the regression 

model is statistically different from zero is indicated 

by a series of asterisks associated with the probability 

of rejecting a true null hypothesis that the 

slope is zero (* = 0.5; ** = 0.01, *** = 0.001 or less). 

Additionally the slopes of each model (XA, YA expressed 

in milliarcseconds/year of movement) and 

various calculations of relative motion (RM, the calculated 

relative motion; CatRM, relative motion from 

published catalog proper motions) and the ratio of 

relative motion to total motion of the primary (RM/ 

PM) are presented. Figure 1 visualizes the relationship 

between R 2 -values of OLS x|epoch and OLS 

y|epoch. Figures 2-6 are visualizations of relative 

motion geometries and further discussed below. Three 

pairs (02581+6912STF 317, 03085-0335BU 528AB 

and 03143+2257BU 530BC) were analyzed for relative 

motion (Table 2) but I was unable to obtain a satisfactory 

series of images to report a measure in Table 

1 One pair reported in Table 1 (03085-0335Fox 

9034CD) had insufficient measures (N = 3) to analyze 

and does not appear in Table 2. 

Discussion 

The methods discussed here are applicable to 

pairs with a long history of observation. The distance 

measure employed herein assumes that motion is linear 

or close to linear. A few of the pairs suspected of 

being long period binaries showed some indications of 

concave motion, but the second-order polynomial fit 

was insignificant and is not reported. (A second-order 

polynomial would not indicate Keplerian motion, but 

might indicate changes in velocity.) Since no pair analyzed 

here had a significant second-order polynomial 

fit, linear motion estimates seem reasonable. However, 

if a significant second-order polynomial fit is 

obtained in future analyses, the integral calculus 

should be employed to check for changes in velocity. 

The results seem to discriminate three classes of 

double stars. The three classes are distinguished by a 

combination of characteristics. 

1. Common proper motion pairs separate from the 

other two classes in (a) showing no significant 

changes in theta and rho over their histories of observation, 

grouping on the bottom left of the OLS analysis 

of the R 2 -values derived from OLS x|epoch and 

OLS y|epoch analyses (blue dots, Fig. 1) and generally 

scoring low on the OLS y|x analysis (Table 2); (b) 

show no correlation between the epoch of observation 

and relative position in Cartesian space, (c) have low 

average relative motions on the order of three (3) 

mas/year (Table 2), and (4) have ratios of relative motion 

to primary total motion of

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Figure 1. Scatter plot of coefficients of determination (R 2 - 

values) derived from OLS x|Epoch (x-axis) against OLS y|Epoch 

(y-axis). Blue circles are pairs classified here as common 

proper motion pairs (CPM). Red circles are pairs classified as 

candidate long period binaries (LPBC), green triangles are pairs 

classified as optical pairs (Optical). STF 326AB, a LPBC, is discussed 

in the text. 

Figure 2. Left: Relative motion of 00089+3713STF 1, an example 

of a pair with a history of tightly clustered history of 

measures showing no significant relative motion between primary 

and secondary. 

Figure 3. Left: Relative motion of 01035+5019 STF 83. An 

example of a pair identified as optical. 

Figure 4. Relative motion of 00502+1150 STF 63AB; typical of 

an optical pair whose relative motion is along the x-axis, resulting 

in a low coefficient of determination (R 2 ).

Vol. 8 No. 2 April 1, 2012 


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Figure 5. WDS 00444+3332STF 54. Although the observations 

form a time series correlated with epoch of observation and 

the relative motion high, as expected for an optical pair, variance 

of individual measures as visualized in this OLS y|x 

analysis result in a relatively low coefficient of determination. 

Dotted lines connect the observations by epoch of observation. 

Figure 6. Relative motion of 02581+6912STF 317. Concave 

motion (albeit not statistically significant) suggests that this 

pair is binary. The relative motion of this pair is about 5 mas/ 

yr, a value slightly higher than the average of common proper 

motion pairs. Both stars have the same parallax values. Dotted 

lines connect the observations by epoch of observation. 

(Continued from page 83) 

rectilinear (Hartkopf et al., 2008 et seq.), have OLS 

y|x analysis that are tightly correlated with motion 

relative to the x and/or y axis, as evidenced by the 

scatter of green triangles on the right side of Figure 1. 

They show a correlation between epoch of observation 

and position in Cartesian space, forming a rectilinear 

time series. They always have at least one highly significant 

score in either the OLS y|epoch or x|epoch 

analysis (Table 2), but may (Fig. 3) or may not (Fig. 4) 

yield a significant model for OLS y|x. The reason for 

the difference is simple, if rectilinear movement is 

along the x-axis, then OLSy|x analysis cannot yield a 

significant model since x-values cannot predict y- 

values. Relative motions also serve to discriminate 

the optical pairs in this study; their relative motions 

average about78 mas/year with a range of 20.88 - 

156.92 mas/year; a range that does not overlap the 

range of average relative motion of CPM pairs. I note 

that the scatter in Figure 1 optical pairs may also be 

caused to simple measurement variation; a pair with 

highly “noisy” measures will yield R 2 -values that are 

lower than less noisy pairs with the same slope (see 

Figure 5 and note the slope is similar to Figure 3 but 

the coefficient of determination is low). Optical pairs, 

have ratios of relative motion to total motion > 0.4 

and usually greater than 1.0 (average = 1.125± 0.539). 

3. The third class is what may be long period binary 

candidate pairs. Their scatter plots and OLS 

analyses place them above the CPM pairs (relative 

motion follows the y-axis) or scattered among the optical 

pairs in Figure 1 where they are plotted as red 

dots. They are similar to optical pairs in forming a 

time series. However, their relative motion average 

motions are more similar to the common proper motions 

pairs. These long-period binary candidates have 

relative motions that average 6.16 mas/year, with a 

range of 1.83 - 8.42 mas/year (excluding STF 326AB, 

discussed below). The pair 02581+6912STF 317 

(Figure 6) is an example; it has one of the higher relative 

motions (7.08 mas/year) and evidence of a slightly 

concave relative motion. Finally, they have ratios of 

total primary total proper motion to relative motion 

comparable (albeit a bit higher) to common proper 

motion pairs (average 0.083±0.051). Components of 

five of these pairs, including STF 317, have similar 

parallax values (Table 2). 

The exception to the generalizations presented 

above is the pair 02556+2652STF 326AB. This pair is 

comprised of two very high proper motion stars with 

an average relative motion of 17.46 mas/yr (placing 

the system within the optical pairs) but a ratio of primary 

proper motion to relative motion of 0.075 

(placing the system within the long-term binary candidate 

pool). This pair has both a rectilinear solution 

(Continued on page 90)

Vol. 8 No. 2 April 1, 2012 


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Table 1. Measures reported in this study. WDS and Disc. Code from the Washington Double Stat Catalog; 

Epoch; epoch of observation; RA, angle of theta in degrees; SEP, separation of the pair in arcseconds; 

PAsd, standard deviation of the angle measures; SEPsd, standard deviation of the separation measures; N, 

number of images from which measures were taken on a single night of observation: a single number indicates 

that all images taken were used, a fractional number denoted the number of “lucky” images used 

out of the total indicated by the denominator. In a few cases images were stacked: 1s/24 denoted a single 

stack of 24 images while 4s/10 indicates that four stacks were compiled from a total of 40 images, 10 

images at a time. Notes, in footnotes. 

WDS Disc. Code Epoch PA SEP PAsd SEPsd N Notes 

00089+3713 STF 1 2009.84 287.4 9.73 0.18 0.026 3/5 1, 2 

00099+0827 STF 4 2009.84 276.1 5.2 0.73 0.061 13/40 1, 2 

00100+4623 STF 3 2009.84 80.44 5.07 0.84 0.082 5/22 1, 2 

00148+6250 STF 10AB 2009.85 175.66 17.64 0.16 0.063 8/10 1, 2 

00152+7801 STF 11 2010.00 191.84 7.97 0.32 0.094 8/27 1, 2 

00174+1631 STF 20 2009.84 233.44 11.884 0.37 0.092 10 1, 2 

00214+6700 STF 26AB-C 2010.00 114.4 13.329 0.67 0.119 4 1, 2 

00316-0202 STF 35 2010.00 265.7 8.43 0.68 0.401 5 1, 2 

00324+0657 STF 36AB 2010.00 82.19 27.133 0.63 0.148 5 1, 2 

00324+0657 STF 36AC 2010.00 227.38 167.241 0.07 0.222 5 1, 2 

00345-0433 STF 39AB-C 2010.00 44.4 16.63 0.91 0.106 5 1, 2 

00345-0433 ALL 1AB-D 2010.00 158.85 202.963 0.04 0.167 5 1, 2 

00399+2126 STF 46 2010.00 196.8 6.215 0.31 0.03 13 1, 2 

00403+2403 STF 47AB 2010.00 205.45 16.41 0.65 0.186 5 1, 2 

00403+2403 BU 1348AC 2010.00 233.06 46.414 0.25 0.124 5 1, 2 

00426+7122 STF 48AB 2010.009 332.31 5.51 0.395 0.036 4s/10 1, 2 

00426+7122 BAZ 1BC 2010.009 318.93 65.75 0.165 0.061 5s/10 1, 2 

00444+3332 STF 54 2010.009 188.58 18.524 0.3 0.104 9 1, 2 

00453+1019 STF 58 2010.009 169.47 46.458 0.2 0.115 10 1, 2 

00474+7239 STF 57 2010.009 197.67 6.197 0.69 0.11 9 1, 2 

00502+1150 STF 63AB 2010.00 248.88 32.417 0.84 0.668 5 1, 2 

00502+1150 BU 1351BC 2010.00 318.05 117.898 0.21 0.439 5 1, 2 

00503+3548 STF 62 2010.009 302.88 11.789 0.21 0.08 9 1, 2 

00538+5242 STF 70AB 2010.009 246.43 7.999 0.2 0.051 20 1, 2 

00538+5242 STF 70AC 2010.009 152.94 74.025 0.1 0.119 20 1, 2 

00546+3910 STF 72 2010.001 173.23 23.39 0.33 0.173 5 1, 2 

01001-0201 STF 81 2010.001 67.24 18.106 0 0 1 1, 2 

01035+5019 STF 83 2010.001 312.38 28.949 0.61 0.252 5 1, 2 

02157+6740 ENG 10 2010.001 328.27 23.228 0.57 0.154 10 1, 2 

Table 1 concludes on next page.

Vol. 8 No. 2 April 1, 2012 


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Table 1 (conclusion). Measures reported in this study. WDS and Disc. Code from the Washington Double 

Stat Catalog; Epoch; epoch of observation; RA, angle of theta in degrees; SEP, separation of the pair in 

arcseconds; PAsd, standard deviation of the angle measures; SEPsd, standard deviation of the separation 

measures; N, number of images from which measures were taken on a single night of observation: a single 

number indicates that all images taken were used, a fractional number denoted the number of “lucky” 

images used out of the total indicated by the denominator. In a few cases images were stacked: 1s/24 

denoted a single stack of 24 images while 4s/10 indicates that four stacks were compiled from a total of 

40 images, 10 images at a time. Notes, in footnotes. 

WDS Disc. Code Epoch PA SEP PAsd SEPsd N Notes 

02216+2338 STF 254 2010.001 14.73 11.904 0.57 0.225 9 1, 2 

02521+3718 STF 316 2010.009 134.67 14.464 0.44 0.083 10 1, 2 

02556+2652 STF 326 2010.009 221.35 4.798 0.59 0.058 4 1, 2 

02558+3429 STF 325AB 2010.009 147.34 22.337 0.34 0.09 5 1, 2 

03018+1051 STF 338 2010.009 201.3 19.848 0.37 0.11 10 1, 2 

03030-0205 STF 341 2010.009 221 8.741 0.79 0.069 10 1, 2 

03066+2038 STF 350 2010.009 118.76 16.502 0.31 0.087 10 1, 2 

03067-1319 STF 356 2010.009 13.41 15.316 0.55 0.114 5 1, 2 

03083-1236 STF 357 2010.009 294.98 8.679 0.88 0.156 10 1, 2 

03085-0335 BU 528AC 2010.009 100.64 51.242 0.178 0.192 10 1, 2 

03085-0335 FOX9023CD 2010.009 155.09 17.444 0.47 0.128 10 1, 2 

03088-0341 STF 358 2010.009 349.28 15.252 0.39 0.183 10 1, 2 

03108+6347 STF 349 2010.009 321.4 5.925 0.99 0.141 18 1, 2 

03143+2257 STF 366AB 2010.009 34.33 41.807 0.1 0.039 10 1, 2 

03203+1944 STF 376 2010.009 250.83 7.14 0.31 0.037 10 1, 2 

03221+6244 STF 373AB 2010.009 118.07 20.323 0.21 0.08 10 1, 2 

03221+6244 STTA 33AC 2010.001 111.73 115.547 0.08 0.104 10 1, 2 

03221+6244 STU 1AD 2010.009 167.53 179.16 0.04 0.158 8 1, 2 

03229+2949 STF 379 2010.009 101.25 10.468 0.75 0.108 10 1, 2 

03242+1733 STF 383 2010.041 119.91 5.466 0.3 0.147 7 1, 2 

03263-0102 STF 393 2010.041 257.29 15.521 0.7 0.163 10 1, 2 

03305+2006 STF 399AB 2010.041 146 19.974 0.31 0.137 10 1, 2 

03313+2734 STF 401 2010.041 269.33 11.506 0.62 0.079 18 1, 2 

05100-0704 STF 651 2010.001 27.94 46.238 0.39 0.296 5 1, 2 

22120+3739 STF2876 2009.85 66.85 11.874 0.36 0.034 5 1, 2 

22542+2801 STF2952AB 2009.85 137.8 17.463 0.32 0.05 5 1, 2 

22542+2801 STF2952AC 2009.85 244.48 165.28 0.04 0.083 5 1, 2 

22567+7830 STF2971 2009.85 3.86 5.44 0 0 1s/24 1, 2 

23092-0719 STF2980 2009.85 107.12 4.585 0 0 1s/10 1, 2 

23519+3753 STF3042 2009.85 86.41 5.642 0.61 0.088 6 1, 2 

Table 1 Notes 

1. 0.3 M Dall-Kirkham Cassegrain, f11.5, SBIG ST8E NABG, with resolution of 0.68 arc seconds/pixel. 

2. 02157+6740 ENG 10 and 23280+2335 STTA246AB used for calibration, measure of 02157+6740 

ENG 10 is control using plate scale and orientation determined from 23280+2335 STTA246AB.

Vol. 8 No. 2 April 1, 2012 


Page 88 


Table 2. Results of OLS and relative motion studies of 59 pairs of doubles stars. WDS, Washington Double 

Star catalog designation; Disc. Code, discovery code; DF, degrees of freedom of OLS analyses (N-1 observations); 

next three columns, Rsq, coefficient of determination of OLSy|x, x|epoch, and y|epoch analyses; 

Asterisk values denote rejection of the null hypothesis in each model that the slope is zero at 0.05 (*), 

0.01 (**) and 0.001 (***) probability; Time, time period between first and last observation used in relative 

motion calculations; XA*1000, slope of the x|Epoch regression model expressed in miliarcseconds/year 

(mas/yr); YA*1000, slope of the y|Epoch regression model expressed in mas.yr; rel-mas/yr, average relative 

linear motion over the Time duration as calculated from relative motion of primary and secondary; cat 

-mas/yr, relative linear motion as calculated from proper motion values in various catalogs; Status, classification 

of pairs as common proper motion pairs (CMP), long-period binary candidates (LPBC) or optical 

WDS Disc. Code DF 

y|x 

Rsq 

x|epoch 

R-sq 

y|epoch 

R-sq 

Time XA*1000 YA*1000 RM Cat RM PM RM/PM Status note 

00089+3713 STF 1 27 0.035 0.002474 0.010 181.004 -0.3211 0.3713 0.49 4.24 19.72 0.025 CPM 

00148+6250 STF 10AB 34 0.144* 0.2115** 0.061 177.79 2.9718 -2.396 3.82 4.47 27.01 0.141 CPM 

00152+7801 STF 11 20 0.179* 0.06261 0.066 178.15 -0.576 1.1823 1.32 0.00 23.09 0.057 CPM 

00174+1631 STF 20 32 0.020 0.08112 0.2096** 184.104 -1.2223 -2.1522 2.48 1.41 43.01 0.058 CPM 

00214+6700 STF 26AB-C 32 0.007 0.02493 0.022 163.26 0.8886 -0.5545 1.05 0.00 25 0.042 CPM 

00316-0202 STF 35 27 0.000 0.002344 0.090 179.84 0.5586 1.945 2.02 0.00 28.18 0.072 CPM 

00324+0657 STF 36AB 62 0.043 0.01002 0.0613* 188.4 -0.9232 1.4854 1.75 6.08 32.35 0.054 CPM 

00345-0433 STF 39AB-C 50 0.035 0.1266** 0.09345* 179.76 -2.6623 -2.786 3.85 8.06 85.15 0.045 CPM 

00399+2126 STF 46 98 0.052* 0.1021** 0.032 178.79 -1.3031 0.9495 1.61 5.10 38.42 0.042 CPM 

00403+2403 STF 47AB 53 0.362*** 0.02073 0.07942* 177.56 -0.8644 1.65 1.86 2.24 43.42 0.043 CPM 

00474+7239 STF 57 7 0.310 0.003132 0.06856** 278.18 -0.1993 1.477 1.49 NA 134.41 0.011 CPM 

00503+3548 STF 62 27 0.079 0.2002* 0.105 177.57 -2.563 -1.1876 2.82 3.60 32.02 0.088 CPM 

00538+5242 STF 70AB 25 0.007 0.0533 0.018 178.16 -1.0817 -1.091 1.54 4.24 81.61 0.019 CPM 

02521+3718 STF 316 33 0.113* 0.1081 0.029 179.99 2.082 0.7789 2.22 8.00 40.5 0.055 CPM 

03018+1051 STF 338 33 0.001 0.02004 0.2051** 180.08 -0.6417 -4.517 4.56 0.00 50.45 0.090 CPM 

03066+2038 STF 350 17 0.424** 0.04788 0.179 179.04 -0.804 -3.762 3.85 5.10 52.43 0.073 CPM 

03083-1236 STF 357 19 0.236* 0.2734* 0.067 176.96 -2.3136 -0.9583 2.50 2.24 81.69 0.031 CPM 

03088-0341 STF 358 12 0.717*** 0.09373 0.064 177.04 -2.846 -6.969 7.53 11.40 50.33 0.150 CPM 

03143+2257 BU 530BC 24 0.131 0.0676 0.073 127.95 0.716 1.149 1.35 NA 28.79 0.047 CPM 

03203+1944 STF 376 50 0.012 0.1228* 0.1172* 227.03 -2.867 1.5159 3.24 7.21 21.4 0.152 CPM 

03221+6244 STF 373AB 15 0.003 0.106 0.000 134.34 2.074 -0.06942 2.08 17.09 45 0.046 CPM 1 

03229+2949 STF 379 84 0.084* 0.028 0.030 179.17 0.4 1.6 1.65 4.01 40.31 0.041 CPM 

03242+1733 STF 383 28 0.431*** 0.02579 0.130 179.49 -1.111 -2.028 2.31 6.08 58.82 0.039 CPM 

03313+2734 STF 401 94 0.011 0.02146 0.1413*** 179.08 -0.8212 1.4884 1.70 7.00 50 0.034 CPM 

22120+3739 STF2876 27 0.079 0.05133 0.064 180.4 -1.0499 -1.0068 1.45 10.44 53.24 0.027 CPM 1 

22567+7830 STF2971AB 52 0.261*** 0.1268 0.4799** 176.96 -3.484 3.522 4.95 1.00 134.85 0.037 CPM 

23092-0719 STF2980 22 0.152 0.1689* 0.006 178.76 2.414 0.1984 2.42 18.29 65 0.037 CPM 1 

00099+0827 STF 3 65 0.333*** 0.2136*** 0.4958*** 187.59 1.6113 -1.6324 2.29 32.31 56.09 0.041 LPBC 1 

00100+4623 STF 4 76 0.106** 0.03484 0.474*** 179.14 -1.1819 -2.0475 2.36 1.41 14.04 0.168 LPBC 

Table 2 concludes on next page.

Vol. 8 No. 2 April 1, 2012 


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WDS 

Table 2 (conclusion). Results of OLS and relative motion studies of 59 pairs of doubles stars. WDS, Washington 

Double Star catalog designation; Disc. Code, discovery code; DF, degrees of freedom of OLS analyses 

(N-1 observations); next three columns, Rsq, coefficient of determination of OLSy|x, x|epoch, and 

y|epoch analyses; Asterisk values denote rejection of the null hypothesis in each model that the slope is 

zero at 0.05 (*), 0.01 (**) and 0.001 (***) probability; Time, time period between first and last observation 

used in relative motion calculations; XA*1000, slope of the x|Epoch regression model expressed in miliarcseconds/year 

(mas/yr); YA*1000, slope of the y|Epoch regression model expressed in mas.yr; relmas/yr, 

average relative linear motion over the Time duration as calculated from relative motion of primary 

and secondary; cat-mas/yr, relative linear motion as calculated from proper motion values in various 

catalogs; Status, classification of pairs as common proper motion pairs (CMP), long-period binary candidates 

(LPBC) or optical pairs (Optical) 

Disc. Code DF 

y|x 

Rsq 

x|epoch 

R-sq 

y|epoch 

R-sq 

Time XA*1000 YA*1000 RM Cat RM PM RM/PM Status note 

01001-0201 STF 81 9 0.291 0.6927** 0.468* 118.12 3.3471 -2.99 4.49 6.40 89.04 0.050 LPBC 

02556+2652 STF 326AB 73 0.944*** 0.9176*** 0.9645*** 178.55 13.62 -21.031 25.06 17.46 330.6 0.076 LPBC 2,3 

02581+6912 STF 317 18 0.709*** 0.6533** 0.8202*** 169.11 4.6231 -2.6147 5.31 5.00 132.25 0.040 LPBC 2 

03030-0205 STF 341 22 0.137 0.5711*** 0.6514*** 

178.58 4.256 5.6188 7.05 17.26 111.2 0.063 LPBC 1 

0.04842** 

03067-1319 STF 356 18 0.056 

0.508*** 178.09 -0.6025 3.019 3.08 6.08 82.08 0.038 LPBC 

* 

03085-0335 BU 528AB 36 0.884*** 0.7881*** 0.8204*** 117.95 2.2586 -5.3782 5.83 NA 34.21 0.171 LPBC 

03263-0102 STF 393 14 0.140 0.582*** 0.001 182.54 5.15 0.2468 5.16 3.16 33.01 0.156 LPBC 2 

03305+2006 STF 399AB 14 0.672*** 0.4316** 0.7677*** 130.36 6.12 -5.408 8.17 4.12 173.35 0.047 LPBC 2 

22542+2801 STF2952AB 11 0.140 0.1268 0.4799** 130.234 -3.484 3.522 4.95 2.00 75.29 0.066 LPBC 2 

23519+3753 STF3042 165 0.313*** 0.7148*** 0.3135*** 186.09 7.7456 -1.6534 7.92 NA 102.54 0.077 LPBC 

00324+0657 STF 36AC 12 0.010 0.9182*** 0.010 116.16 -40.051 1.798 40.09 41.98 32.35 1.239 Optical 

00345-0433 ALL 1AB-D 3 0.347 0.9973*** 0.332 77.99 -94.829 9.232 95.28 85.15 85.15 1.119 Optical 

00403+2403 BU 1348AC 17 0.036 0.9269** 0.121 177.59 -39.371 3.126 39.49 45.54 43.42 0.910 Optical 

00426+7122 STF 48AB 59 0.112** 0.05274 0.013 181.02 -62.58 0.428 62.58 40.80 43.9 1.426 Optical 1 

00426+7122 BAZ 1BC 3 0.612 0.9212** 0.344 78.31 -114.9 -38.2 121.08 86.05 66.19 1.829 Optical 1 

00444+3332 STF 54 18 0.32** 0.781*** 0.523*** 179.71 11.963 5.906 13.34 14.87 10.63 1.255 Optical 

00453+1019 STF 58 11 0.74*** 0.8046*** .6472*** 112.12 20.401 9.846 22.65 24.52 18.38 1.232 Optical 

00502+1150 BU 1351BC 8 0.901*** 0.9953*** 0.9247*** 110.31 101.5 -16.671 102.86 58.60 130.18 0.790 Optical 1 

00502+1150 STF 63AB 37 0.12* 0.9979*** 0.1229* 177.6 -156.081 3.308 156.12 152.05 69.03 2.262 Optical 

00538+5242 STF 70AC 9 0.612** 0.9634*** 0.6888** 106.06 -87.488 -16.819 89.09 95.13 81.61 1.092 Optical 

00546+3910 STF 72 24 0.695*** 0.9503*** 0.6565*** 178.24 22.251 -6.7017 23.24 19.92 28.28 0.822 Optical 

01035+5019 STF 83 8 0.986*** 0.9334*** 0.8771*** 182 -63.73 -56.949 85.47 70.76 116.4 0.734 Optical 1 

02216+2338 STF 254 49 0.372*** 0.9759*** 0.4392** 178.26 46.492 4.636 46.72 50.24 23.54 1.985 Optical 

02558+3429 STF 325AB 45 0.987*** 0.9973*** 0.9862*** 179.03 130.3 88.76 157.66 158.93 12.6 12.513 Optical 

03085-0335 BU 528AC 3 0.629 0.788* 0.9564** 113.94 5.128 23.908 24.45 22.20 34.21 0.715 Optical 

03143+2257 STF 366AB 23 0.712*** 0.9852*** 0.6653*** 132.11 -69.362 13.661 70.69 72.27 60.67 1.165 Optical 

03221+6244 STTA 33AC 14 0.020 0.8319*** 0.095 134.34 -17.305 -6.203 18.38 16.64 45 0.409 Optical 

03221+6244 STU 1AD 5 0.431*** 0.9687*** 0.9556*** 109.1`1 -31.011 -44.512 54.25 46.23 45 1.206 Optical 1 

05100-0704 STF 651 55 0.912*** 0.9139*** 0.9837*** 180.33 56.706 -232.996 239.80 242.79 247.39 0.969 Optical 

22542+2801 STF2952AC 15 0.112 0.7074*** 0.4384** 55.19 80.42 -24.661 84.12 103.81 75.29 1.117 Optical 

Table 2 Notes 

1. Average relative motions differ by more than 9 mas/yr. 

2. Both components have similar parallax measures. This is only reported for these pairs, other pairs 

may have similar or different parallax measures. 

3. See text for discussion of this pair

Vol. 8 No. 2 April 1, 2012 


Page 90 



and a proposed orbital solution (note “C” in the WDS). 

In fact, all of the long-term binary candidates will 

have rectilinear solutions given that their relative 

motions are not significantly different from a rectilinear 

motion solution. Is STF 236AB optical or binary 

Kharchenko and Roeser (2009: CDS catalog I/280B) 

list three trigometric parallax measures for this system, 

one composite (based on reported magnitude and 

position) with high error and proper motions that appears 

suspect (parallax -63.09 ± 49.9, pmRA 520.84 

mas/yr, pmDec -48.79 mas/yr) and two matching the 

pair in proper motion and magnitude that yield 

trigometric parallax measures of 43.7 ± 1.25 mas (A 

component) and 43.9 ± 1.25 mas (B component), suggesting 

that this pair is physically associated and belongs 

to the LPBC category. 

I have chosen to classify a number of pairs as long 

period binary candidates to bring them to the attention 

of the community. At least some of these pairs 

seem to be physically associated, as evidence by similar 

parallax measures. However, none of these data 

definitively corroborates these pairs as binary. It is 

quite possible that even those at similar distances are 

simply common proper motion pairs that are diverging 

or converging. They may even be optical pairs 

that just happen to be in the same area with similar 

proper motions. Only a longer history of observations 

will reveal their nature, but identifying them as possible 

binaries may encourage continued observation 

and measurement. 

The contrast between relative motions determined 

from studying theta and rho and those taken 

from catalogs is instructive. For example, 00538+5242 

STF 70AB has a simple change of sign in the WDS 

that makes relationship appear to be optical, but the 

actual data in the WDS individual record is correct. 

The catalog values for 004240.01+712157.3 STF48AB 

are at variance with those values obtained through 

relative motion and the same is true for a number of 

the pairs included in this study (10 in total, see Table 

2). 

Conclusions 

Relative motion studies are well within the capabilities 

of amateur researchers who have access to a 

program that can calculate OLS models. Although I 

used R-language programming, the regression functions 

in data analysis package of Excel® return similar 

models and are probably more than adequate for 

this level of analysis. The nature of long-period binaries 

cannot be resolved until their motions are shown 

conform to Keplerian motion, but these methods may 

help resolve the nature of some double stars, given a 

long history of observation and sufficiently high 

proper motions, and may help mark pairs for additional 

measures in the future. They also seem useful 

for checking catalog proper motion values. 



Double Star Catalog and the Catalog of Rectilinear 

Elements maintained at the U.S. Naval Observatory. 

Various resources of the CDS, Strasbourg, France 

(Bonnarel et al., 2000), were used in this study including 

Aladin, POSS and 2MASS images, and the 

Tycho-2 (Hog et al., 2000), Hipparchos (ESA, 1997), 

All-sky compiled catalogue (Kharchenko and Roeser, 

2009) and PPMXL (Roeser et al., 2010) catalogs. My 

thanks to Dr. Brian Mason (USNO) for fulfilling numerous 

data requests. Dr. Bill Hartkopf (USNO) answered 

numerous questions with good humor. Florent 

Losse (REDUC, http://www.astrosurf.com/hfosaf/ 

index.htm), Dr. R. Kent Clark (University of South 

Alabama) and Dr. Richard Branham (Regional Center 

for Scientific and Technological Research, Mendoza, 

Argentina) reviewed earlier versions of the study and 

I thank them for their valuable comments. My thanks 

to Frank Smith (Jaffrey, NH) who provided valuable 

and extensive comments on version 2 of the manuscript. 

An anonymous reviewer provided a valuable 

formal review; my thanks. Thanks to Arnie Rosner 

and Brad Moore, Global Rent-A-Scope, (http:// 

wiki.global-rent-a-scope.com/) for their support of research 

to the Remote Astronomical Society Observatory 

and to Mike and Lynne Rice of New Mexico Skies 

(http://www.nmskies.com/) for ground support for the 

observatory. Special thanks to Dr. Christian Sasse for 

allowing me time on his telescope to perform the 

“lucky imaging” that made this research possible. 

References 

Bonnarel, F., Fernique, P., Bienayme, O., Egret., D. 

Genova., F., Louys, M., Ochsenbein, F., Wenger, 

M., & Bartlett, J. G., 2000, Astron. Astrophys., 

Suppl. Ser. 143, 33-40. 

Branham, R. L. 2001. Astronomical data reduction 

with total least squares. New Astronomy Reviews, 

45, 649–661. 

Hartkopf, W. I., Mason, B. D., Wycoff, G. L. & Kang, 

D. 2008 et seq., Catalog of Rectilinear Elements.

Vol. 8 No. 2 April 1, 2012 


Page 91 


U. S. Naval Observatory, Washington, D. C., online. 

Hog E., Fabricius C., Makarov V.V., Urban S., Corbin 

T., Wycoff G., Bastian U., Schwekendiek P., 

Wicenec A. 2000. Astron. Astrophys. 355, L27. 

Ihaka, R., Gentleman, R. (1996). "R: A Language for 

Data Analysis and Graphics". Journal of Computational 

and Graphical Statistics 5 (3), 299–314. 

Kharchenko, N. V. and S. Roeser. 2009. I/280B, Allsky 

complied catalogue of 2.5 million stars, (ASCC 

-2.5, 3rd edition). VizieR on-line data. 

Losse, F. 2010 et seq. REDUC. http:// 

www.astrosurf.com/hfosaf/index.htm 

Mason, B. D., 2006, JDSO, 2(1), 21-35. 

Mason B.D., Wycoff G.L., Hartkopf W.I., Douglass 

G.G., Worley C.E. 2010. Wasington Double Star 

Catalog. Astron. J., 122, 3466 (2001-2010) 

Roeser S., Demleitner M., Schilbach E. 2010. Astron. 

J., 139, 2440. 

Wiley, E. O. 2010. JDSO, 6(3), 217-224. 

APPENDIX A – Using Optical Pairs to 

Derive Orientation and Scale in REDUC 

REDUC uses two values to reduce theta and rho 

for a double star, the orientation of the camera relative 

to the optical train and the scale of the image. 

These are determined by inputting into the program 

an image of known theta and rho, from which RE- 

DUC calculates the parameters. Amateurs using CCD 

measures may not have a convenient WDS calibration 

pair, but there are numerous “high-value” pairs in the 

Catalog of Rectilinear Elements that can serve this 

purpose and which are separated enough that relative 

long exposures can insure adequate determination of 

the centroids. I simply search for pairs with low errors 

for all elements and separations of at least 10 

seconds of arc. The angle and separation for the pair 

on any given data can be determined by first computing 

the x,y positions in Cartesian space and then converting 

these to the angle and distance (with due regard 

to quadrant). It is a simple matter to check the 

result against the published ephemeris values to 

check against gross error. The formulae for x and y 

are given in the catalog: 

x = xa 

( t− t0) 

+ x0 

y = ya 

( t − t0) 

+ y0 

Where t 0 is the time of closest approach, t is the date 

of observation, x 0 and y 0 are the positions at time t 0 in 

the Cartesian system, and x a and y a are the slope and 

the normal. For the pair 21144+2905 STF2779AB, the 

calculations proceed as shown for the observation 

date 2009.844. 

x = 0.37006*(2009.844-2011.018) + 7.60913 

= 3.8651 

y = -0.022599*(2009.844-2011.018) + 12.459682 

= 14.7451 

tangent (first quadrant) = y/x = 3.8149 

Angle (first quadrant) = 75.3112° 

Theta 2009.844 = 165.31º (90°+75.31°) 

Rho 2009.844 = 15.244 seconds of arc 

The trick is determining the correct quadrant, but 

this can be easily determined from the Ephemeris of 

the WDS Rectilinear catalog and each angle will have 

to be determined separately. This compared very favorably 

with the WDS Ephemeris values for 2010 of 

165.3º and 15.242 second of arc. As an additional 

check, one can calculate the ephemeris of a second 

pair, image and measure that pair using the Delta 

(orientation) and E-values (scale) derived from the 

first standard pair, as reported for 02157+6740ENG 

10 in Table 1. I do this routinely as it is relatively 

simple to find another pair using the information in 

the catalog.

Vol. 8 No. 2 April 1, 2012 


Page 92 

Observation Report for the Year 2009, 

Humacao University Observatory 

R. J. Muller, J.C. Cersosimo, D. Centeno, L. Rivera-Rivera, E. Franco, V. Maldonado, 

M. De Jesus, R.A. Rodriguez, A.J. Sosa, M. Rosario, M. Diaz 

Humacao University Observatory 

Department of Physics and Electronics 

The University of Puerto Rico at Humacao 

Call Box 860, Humacao, Puerto Rico 00792 

E-mail: rjmullerporrata@gmail.com 

Abstract: We report measurements of position angle and separation of 120 binary stars 

observed during the year 2009. We obtained the data using the 31 inch NURO Telescope 

at the Anderson Mesa location of Lowell Observatory near Flagstaff, Arizona, in May and 

September. We gathered the data using the 2K x 2K CCD camera - NASACAM - at the 

prime focus of the telescope. The data was analyzed at the Humacao University Observatory. 

Introduction 

We imaged 120 binary systems at the prime focus 

of the 31 inch NURO telescope in the year 2009. 

The observation sessions took place on May 28, 29 

and 30; a second session took place on September 19, 

20 and 21, for a total of six nights at the NURO telescope. 

Clouds forced the partial cancelation of one 

night in May. Two students traveled to observe and 

obtain data in May. Three traveled in September. 

We used the NASACAM CCD, a 2048 X 2048 array, 

thermoelectrically cooled below -100 Celsius, with a 

field of view of approximately 16 arc minutes by 16 arc 

minutes. 

Procedure 

All images needed for calibration and the images 

of the binaries where obtained and sent to the 

Humacao University Observatory for analysis. Undergraduates 

pursuing research projects at the observatory 

calibrated and examined the images to 

make sure that our targets where present on the 

CCD images. Doubtful images where discarded. The 

students used the pixelization of the calibrated images 

as a tool for the measurement of separation; the 

position angle was measured directly. Many of the 

CCD images where also examined using the software 

that is included with the Handbook of Astronomical 

Image Processing for Windows, 2 nd Edition, by Richard 

Berry and James Burnell, Willman-Bell Inc, Virginia 

(http://www.willbell.com) 2006. The Handbook 

includes the CD AIP for Windows (II). There is a feature 

in the CD that, with some care, will give accurate 

values for separation and position angle directly 

from the CCD image. Since there is a reducer on the 

optical path to the CCD, the images we acquire are 

mirror reversed with respect to the program's position 

angle routine, so one must have lots of care 

when one is measuring position angle with the program. 

The software does not provide for entering the 

plate scale of the optical system, so the final number 

crunching must be done by hand. 

There is a systematic error in position angle that 

occurs when the CCD camera is inserted into the 

telescope, or the CCD is not “leveled” when the telescope 

is pointing at the north pole. This error can be 

corrected by using well known binary systems and 

binary systems that “don’t move”. Binary systems

Vol. 8 No. 2 April 1, 2012 


Page 93 


that “don’t move” can be found in the neglected section 

of the Washington Double Star catalog, as binary 

stars that have been measured for the last 100 years 

and show no change in position angle. We correct for 

this uncertainty by using a mix of images of well 

known binaries and of those that “don’t move”. We 

corrected the position angle of binaries submitted in 

this article for this effect by using about 30 of them to 

calculate the systematic error we call the CCD offset. 

The table that follows includes 120 entries, all of 

them for 2009. It follows the standard JDSO format 

and ordering. 


This research has made extensive use of the 

Washington Double Star Catalog, maintained at the 

U.S. Naval Observatory, and of the NURO telescope, 

property of the Lowell Observatory. We would like to 

acknowledge support from the Puerto Rico Space- 

Grant Consortium and the L.S.AMP of the University 

of Puerto Rico. We also thank Ed Anderson of the 

NURO consortium and the University of Northern 

Arizona for his efforts on behalf of our students. 

UPRH UPRH 

Name RA DEC Mags 

Date 

ρ 

θ 

HJ 154 12 02 49.71 +28 41 15.3 10.0 11.0 21.2 89.66 0.402 

GRV 849 12 02 53.16 +23 45 50.8 11.7 12.0 28 230.66 0.402 

STI 738 12 03 17.7 +59 24 05 12.24 13.1 6.9 44.66 0.402 

STF1594AC 12 03 28.5 +41 24 15 10.09 11.1 11 145.66 0.402 

BAL1450 12 03 11.85 +00 43 48.8 11.51 12.4 22.7 208.66 0.402 

POU3120 12 04 05.7 +23 11 41 11.09 13.1 14.5 195.66 0.402 

BU 458 12 04 17.11 -21 02 21.0 7.87 9.97 29.9 233.16 0.402 

KZA 26 12 05 07.7 +43 22 47.4 10.5 10.5 17 108.16 0.402 

HJ 4496 12 06 12.76 -18 53 27.9 10.05 10.98 12.2 29.66 0.402 

HJ 519 12 30 26.33 +36 07 44.7 10.32 10.35 18.1 188.66 0.402 

ES 726AC 12 30 49.2 +53 51 27 10.48 13.6 20 180.66 0.402 

STF1650 12 31 32.99 +24 37 13.1 9.54 10.47 16.5 179.16 0.402 

LDS4224 12 32 13.2 +31 47 19 14.5 15.4 10.85 311.66 0.402 

HJ 211 12 32 21.1 -01 53 33 11.86 12.3 11 278.66 0.402 

LDS3049 12 32 26 +30 50 24 14.22 14.63 18.59 122.16 0.402 

LDS4225 12 32 28.75 +28 54 12.4 13.3 15.3 16.7 203.66 0.402 

LDS3051 12 33 19. +52 27 00 15.9 17.1 15.5 358.66 0.402 

POU3152 13 49 38.9 +23 28 15 12.25 12.30 13.6 2.66 0.402 

HJ 542 14 12 18 +36 46 12.0 12.0 12.4 66.66 0.402 

POU3162 14 13 24 +24 24 12.02 13.8 6.8 346.66 0.402 

κ Bootis 

STF 1821 

May 2009 measurements. 

14 13 29 +51 47 4.53 6.62 13.3 231.66 0.402 


Vol. 8 No. 2 April 1, 2012 


Page 94 


May 2009 measurements (continued). 


ι Bootis 

STFA 26AB 

14 16 10 +51 22 4.76 7.39 38.9 35.16 0.402 

ES 1085 14 16 30 +46 33 8.71 11.7 5.7 177.66 0.402 

LDS4521 15 00 47.5 +23 06 26 16.3 17.3 25.7 340.16 0.402 

STF1901 15 00 57.70 +31 22 38.2 8.71 10.55 19.1 186.16 0.402 

HJ 1266 15 01 08.0 +04 15 17. 10.77 12.1 13.1 25.66 0.402 

LDS4543 15 20 41 +26 38 12.6 18.3 54 234.66 0.402 

KZA 80 15 20.7 42 +31 33 12.41 12.9 25.1 57.66 0.402 

KZA 90 15 27 24 +31 02 12.5 13.0 19.1 298.16 0.402 

POU3193 15 35 18 +24 08 13.2 13.7 7.6 299.16 0.402 

STF1999AB 16 04 25 -11 26 57 7.52 8.05 12 99.66 0.402 

HJ 582 16 07 06 +35 07 11.11 13.61 22 232.66 0.402 

ALI 370 16 07 24 +35 48 12.06 12.5 12.4 144.66 0.402 

POU3214 16 07 48 +23 06 11.1 13.3 12.4 87.66 0.402 

STF2010AB 16 08 04.5 +17 02 49 5.10 6.21 25.9 12.66 0.402 

STF2032AB 16 14 40.85 +33 51 31 5.62 6.49 4.5 243.66 0.402 

KZA 120 16 53 22.06 +46 01 30.9 10.5 10.5 11.1 81.66 0.402 

BAL2429 16 54 51.2 +03 18 41 11.77 12.8 12 49.16 0.402 

SLE 76 17 00 18 +33 12 12.07 12.8 8.36 18.66 0.402 

STF2123 17 06 57.50 +06 48 03 9.82 9.98 18.2 218.66 0.402 

STF2127 17 07 04.42 +31 05 35.1 8.70 12.30 14 280.66 0.402 

SLE 9 17 07 06.29 +20 29 21.7 10.49 11.94 20.1 173.91 0.402 

ARA1121 17 07 06.2 -20 14 44 11.8 12.4 7.6 216.66 0.402 

SLE 110 18 07 14.5 +27 16 04 10.56 13.3 10.8 117.16 0.402 

STI2369 18 07 29.23 +55 14 31 12.3 12.6 15.34 191.66 0.402 

BAL1952 18 07 34.4 +02 24 08 11.52 12.8 13.9 154.66 0.402 

POU3350 18 07 59.9 +24 06 00 11.8 12.0 9.1 61.66 0.408 

BAL2474 18 08 03.4 +03 43 12 10.0 11.0 14.9 280.16 0.408 

POU3351 18 08 08.8 +23 27 12 12.05 13.9 10.4 152.66 0.408 

BAL2483 18 14 41.6 +03 42 05 212.00 12.7 13.06 191.66 0.408 

POU3380 18 17 22. +24 56 36 12.20 13.03 13.2 76.66 0.408 

BEM 37 19 01 24 +53 28 11.87 11.90 11.5 309.66 0.408 

STF2459 19 07 22.01 +25 58 23.9 9.12 10.07 14.6 236.66 0.408 

UPRH 

ρ 

UPRH 

θ 

Date 


Vol. 8 No. 2 April 1, 2012 


Page 95 


September 2009 measurements 


LDS4622 16 01 47 -04 47 48 12.4 16.2 14.85 38.5 0.715 

HJ 580 16 02 50.56 + 37 05 26.8 9.20 12.2 43 7.5 0.715 

BEM 21 16 02 58.26 +51 11 40.4 10.54 11.02 19.04 104 0.715 

BAL1911 16 03 20.00 +02 31 26.8 12.19 12.7 17.77 233.5 0.715 

STF1999AB 16 04 25.9 -11 26 57 7.52 8.05 11.59 98 0.715 

ARA 433 16 06 35.8 -18 19 11 11.6 14.1 10.05 54.5 0.715 

HJ 582 16 07 06 +35 07 00 9.7 12.0 22.75 232 0.715 

ALI 370 16 07 26.8 +35 48 29 12.06 12.5 12.73 147.5 0.715 

POU3214 16 07 48.8 +23 05 29 11.1 13.3 12.40 83 0.715 

STF2010AB 16 08 04.5 +17 02 49 5.10 6.21 25.62 12 0.715 

HJ 1289 16 10 38.01 +39 28 38.2 11.39 12.3 11.48 239 0.715 

GRV 924 16 11 43.26 +35 07 29.1 8.8 12.1 10.35 308.5 0.715 

HJ 1288 16 12 40.8 -16 45 18 11.0 12.3 19.0 124 0.715 

ES 627 16 18 35.71 +51 19 51.5 9.88 10.98 11.70 288.5 0.715 

BAL2429 16 54 51.2 +03 18 41 11.77 12.8 11.40 51 0.715 

LDS4705 16 56 24.44 +03 30 29.1 15.2 17.0 13.90 53.5 0.715 

BAL1486 17 05 55.9 +00 55 57 10.86 12.4 7.40 12.5 0.715 

BAL1931 17 06 09.8 +02 06 05 11.4 11.5 18.10 188.5 0.715 

COU 109 17 06 27.9 +22 07 57 10.01 13.1 8.64 139 0.715 

SLE 78BC 17 06 49.8 +33 56 00 11.27 12.15 14.70 204 0.715 

LDS 988 17 06 56.77 +06 47 48.2 17.8 39 0.715 

STF2123 17 06 57.50 +06 48 03 9.82 9.98 18.86 217 0.715 

AG 353 17 07 01.4 +12 13 22 9.83 11.7 10.40 249 0.715 

STF2127 17 07 04.42 +31 05 35.1 8.70 12.30 14.8 276 0.715 

SLE 9 17 07 06.29 +20 29 21.7 10.49 11.94 20.1 174 0.715 

GRV 946 17 07 14.12 +25 44 34.5 10.54 11.7 20.5 40 0.715 

HJ 1314 18 07 05.32 +32 22 54.6 10.33 11.09 18 151 0.715 

SLE 110 18 07 14.5 +27 16 04 10.56 13.3 10.7 110 0.715 

BAL1952 18 07 34.4 +02 24 08 11.52 12.8 13.6 154.5 0.715 

STF2280AB 18 07 49.5 +26 06 04 5.81 5.84 14.1 177 0.715 

BAL2474 18 08 03.4 +03 43 12 10.0 11.0 15.35 282 0.715 

POU3351 18 08 08.8 +23 27 12 12.05 13.9 10.25 159 0.715 

SLE 111 18 08 53.9 +27 24 56 10.8 12.5 14.7 315 0.715 

POU3353 18 08 55.1 +23 19 00 12.26 12.4 15.55 342 0.715 

UPRH 

ρ 

UPRH 

θ 

Date 


Vol. 8 No. 2 April 1, 2012 


Page 96 


September 2009 measurements (continued) 


STF2293 18 09 53.83 +48 24 05.7 8.08 10.34 13.4 85 0.715 

HJ 1315 18 09 53.5 +29 41 16 11.85 13.1 10.1 132 0.715 

ARA 267 18 09 54 -17 09 38 11.22 11.5 14.9 345.5 0.720 

SEI 559 18 10 27.8 +33 55 55 11.0 11.0 11.67 171 0.720 

BAL2481 18 10 37.2 +03 27 23 11.3 11.3 10.98 109.5 0.720 

AG 217 18 11 05.89 +53 29 37.8 10.77 11.85 14.29 237.5 0.720 

ALI 140 18 11 25.14 +35 06 45.5 10.97 11.79 14.43 253 0.720 

BAL2483 18 14 41.6 +03 42 05 12.00 12.7 13.1 195 0.720 

SLE 145 18 14 58.3 +03 03 43 11.2 11.9 11.94 27 0.720 

STF2459 19 07 22.01 +25 58 23.9 9.12 10.07 15.28 230.5 0.720 

POU3718 19 08 00.6 +24 58 09 10.69 13.7 14.41 270.5 0.720 

HJ 877 19 10 04.2 +19 33 15 10.8 11.1 12.5 295.5 0.720 

SLE 931 19 10 20.34 +02 49 58.7 9.9 12.0 11.62 80 0.720 

POU3745 19 12 00.7 +23 46 18 12.47 13.7 10.92 21 0.720 

HJ 1375 19 12 34 +28 14 47 11.02 13.64 12.39 84 0.720 

HLM 18 19 13 15.0 +39 08 57 10.94 11.33 12.7 332 0.720 

SLE 935 19 14 26.74 +02 12 06.2 11.0 11.0 8.83 219.5 0.720 

ARA1175 19 15 30.0 -19 55 19 11.60 12.5 12.5 14.5 0.720 

HJ 2861 19 16 30.4 +07 12 10 10.84 13.8 12.01 56 0.720 

BAL1516 19 17 00.2 +01 45 03 11.03 11.1 11.2 272 0.720 

HJ 2868 19 17 56.9 +58 07 58 11.9 11.9 11.57 100 0.720 

SEI1012 20 13 02.3 +34 50 28 11.0 11.0 14.79 50.5 0.720 

CHE 235 20 14 36.6 +14 52 35.2 10.0 11.5 13.8 28.5 0.720 

STI2586 21 42 40.45 +56 14 56.9 10.71 11.72 12.55 3 0.720 

STI2720 22 21 30.0 +58 36 48 12.1 12.1 14.57 160 0.720 

STI2722 22 21 59.1 +56 19 52 10.67 13.1 14.35 72 0.720 

STI2872 22 50 16.7 +57 36 20 11.85 11.9 10.88 55 0.720 

STF2999AD 23 18 46.4 +05 11 18 8.90 11.9 27.02 20.5 0.720 

STI3007 23 36 42.8 +58 19 49 13.2 13.2 9.14 123.5 0.720 

STI3012 23 38 24.5 +58 00 27 12.6 12.6 7.96 100.5 0.720 

BAL1249 23 41 02.7 +00 43 07 10.36 12.4 14.2 337.5 0.720 

STF 23AB 00 17 28.7 +00 19 15 7.88 10.28 9.6 217.5 0.720 

BAL1611 00 43 18.50 +02 51 01.2 11.4 11.5 19.5 181 0.720 

UPRH 

ρ 

UPRH 

θ 

Date

Vol. 8 No. 2 April 1, 2012 


Page 97 

CCD Measurements of Espin’s Neglected Double 

Stars: First in a Series 

Juan-Luis González Carballo 

Foro Extremeño de Astronomía, FEXDA 

Agrupación Astronómica de Sabadell, AAS 

Observatorio Cerro del Viento, MPC I84 

Badajoz, Spain 

struve1@gmail.com 

Abstract: In this paper I present the first in a series of CCD theta/rho measurements of 

double stars from T. H. E. C. Espin’s catalog. In this project, I focused on the neglected doubles. 

I report here the first 100 measures. In addition, during this campaign, I found six 

new double stars, either new closed components of some of Espin’s systems or new common 

proper motion doubles of nearby pairs. 

Introduction 

A few months ago I observed on the same night 

several double stars with the initials “ES”. I was 

surprised by the number of them occupying a 

small portion of the sky, and I thought about finding 

information on the astronomer hiding behind 

those letters. Then, I remembered a lovely old photograph 

featuring Thomas Espin, which I had 

found some time ago. I had even used it for one of my 

blog’s posts. 

Shortly there after, I began my little research on 

this great English astronomer of the late 19 th century 

and the first third of 20 th , as I was hooked not only 

by his extraordinary capacity for work, but also by 

the passion he felt for double stars. Accordingly, I 

decided to dedicate a good portion of my time as a 

doubles’ observer to track down all the Espin stars 

I could. I contacted Dr. Brian D. Mason, fo the U.S. 

Naval Observatory, who kindly sent m a complete 

filtered list with all the stars that appear 

as neglected in the WDS. 

Even though the task seemed daunting, I decided 

to steel myself to get down to work, inspired by the 

similar work developed my friend and colleague 

Edgar R. Masa Martin from Valladolid 

(Spain) in the case of Stein. A total of 447 stars had 

not been observed over the last 20 years, considering 

them therefore as neglected. A little planning 

helped me to appreciate the opportunity to develop 

this enterprise and I started my observations 

at the end of 2009. Today, after 16 observation 

sessions, I can state that I have seen 80% of these 

doubles. 

In this paper, I present the first series of neglected 

doubles of Espin: 100 pairs. The rest will appear 

in subsequent works. In addition, thanks to 

the work done, I could detect some new and uncataloged 

double stars, both pairs with common proper 

motion (CPM) in the vicinity of Espin stars, and new 

closed components of some systems cataloged by our 

dear English amateur astronomer. 

About Espin 

The Rev. Thomas Henry Compton Espinell Espin 

was born May 28, 1858, in Birmingham, England. He 

received a good education, first at home through the 

attentions of his father, and later at Haileybury and 

Imperial Service College of Hertford to complete his 

training at Exeter College, Oxford University, where 

he graduated with honours in 1881. Just one year 

later he was ordained a deacon and months later he

Vol. 8 No. 2 April 1, 2012 


Page 98 


was consecrated as a pastor. Between 1882 and 1885, 

he held the position of assistant in the parishes of 

West Kirby and Wolsingham; he stayed there until 

1888 when he was appointed permanent pastor of the 

nearby church of Saint Philip and Saint James of the 

small town of Tow Law. He remained there until his 

death in 1934 at the age of 76. 

In Tow Law he would lead a quiet and pleasant 

life with full dedication to his position and, of course, 

hobbies. He was known to spend nights at the observatory, 

even in adverse weather conditions. Along 

with his church, he enjoyed a comfortable vicarage 

surrounded by gardens. Espin was a lover of an orderly 

life and he had a soft spot for cats, which accompanied 

him on his nights at the observatory (Figure 

1). 

In addition to his work as a clergyman and astronomer, 

Espin was interested in many fields of science: 

he was a pioneer in the use of astronomical photography, 

spectroscopy and the use of X-rays applied 

to medicine (as he did to build a hospital in his homeland 

for the care of tuberculosis). Likewise, he developed 

an equal interest in botany and geology. 

Espin was, undoubtedly, a well-known astronomer 

of his time, not only for his tireless efforts in the 

observation, but also for the discovery of double stars. 

He developed a fulfilling career as a researcher, while 

promoting associative work among amateur astronomers 

of his country -an odd curiosity in a lonely person 

like him. 

The beginning of his interest in the heavens 

seems to have started at the early age of 14 while he 

was a student at Haileybury College, around 1873. A 

professor, F.J. Hall, aroused his curiosity in astronomy, 

enjoying his first telescopic observations in the 

small observatory at the college. Only 18 months after 

his baptism as astronomer, on January 11, 1878, he 

was elected Fellow of the Royal Astronomical Society 

(RAS), a fact completely unusual due to the youth of 

the new member, thus becoming the youngest ever 

elected. 

At that time he began to publish his observations 

with some frequency in smaller publications such as 

English Mechanics. In those astronomical formative 

years he established important contacts with leading 

astronomers: - Thomas W. Webb, whom he helped in 

the compilation of his book of Celestial Objects (he 

was in charge of the following editions of this book), 

and the Professor of the Savilian Chair of the University 

of Oxford Charles Pritchard, who served as his 

mentor in the working sessions at the telescope until 

he graduated at this University. 

Figure 1: Thomas Espin with one of his loving cats 

(Courtesy of Mrs. Pauline Russell, University of Durham). 

Also in those years, he began to develop the idea 

of creating an astronomical club in Liverpool. As a 

result, the Liverpool Astronomical Society was set up 

formally in 1881, with Espin a founding member. It 

wasn’t the last association that he promoted, because 

in 1904 we find him doing the same with the Newcastle 

Astronomical Society; he would be its president 

until his death in 1934. Espin was also a founding 

partner of the leading amateur club in Great Britain, 

the British Astronomical Association, besides being 

either an honorary member or correspondent for other 

associations around the world. 

There is no doubt that one of the most glorious 

moments in his astronomical life was the discovery of 

a nova in the constellation of Lacerta, known as Nova 

Lacertae 1910 (currently DI Lac). It reached a brightness 

of 4.6, decreasing for 37 days to end up in its 

usual magnitude (between the 14th and 15th). Espin 

discovered it on December 30 of that year while observing 

double stars in that region of the sky just af-

Vol. 8 No. 2 April 1, 2012 


Page 99 


Figure 2: Th. Espin (left) and W. Milburn at the 6 meters Tow 

Low’s Observatory (Courtesy of Mrs. Pauline Russell, University 

of Durham). 

ter the sunset and noticed that this bright star was 

not in their charts of Argelander. He ran from the 

observatory to the vicarage to get its spectroscope to 

try to obtain the spectrum of the new star. Half an 

hour later he ran again, this time to the post office to 

send a telegram to the Greenwich Observatory, where 

the discovery was reported to Harvard and where 

photographs were taken that night. As a reward, in 

1913 he was awarded the Jackson-Gwilt Medal of the 

RAS. By then he had the help of a promising young 

man, William Milburn (MLB in WDS), whom he hired 

as an assistant and who would work with him until 

the end of his life. 

After that time, he focused his work almost exclusively 

on the cataloguing of new pairs of double stars, 

amounting to several thousand in his mature years. 

However, he still had time to discover as many as 20 

variable stars and deep sky objects that are entered 

into the Index Catalog (IC), including emission nebulae, 

open clusters and even a planetary nebula. 

The relatively comfortable position enjoyed by 

Espin over his life allowed him to have a scientific 

and astronomical equipment that was very advanced 

for his time. After taking office in 1885 in the parish 

of Wolsingham, he achieved a stability that resulted 

in his most productive years of astronomical dedication. 

And after enjoying the various scientific instruments 

and telescopes, of increasingly larger diameter 

and sophistication, he finally built an observatory six 

meters (Figure 2) in diameter to host 

a large telescope: the giant 17.25 "(438 mm) reflector. 

The observatory had to be moved, three years later, to 

Tow Law when, in 1888, Espin received his final destination 

in the parish of the town. However, in 1914, 

his aspiration to have an even bigger telescope, led 

him to acquire the 24" (609 mm) Calver reflector, giving 

the use of 17.25" to Milburn. 

For the rest of his life, he remained an observer 

until the age of 74, only two years before his death. 

He was devoted to the observation of double stars and 

had a true passion for their observation and cataloging. 

His list of publications on the subject is very long, 

especially after 1912 when he was helped by Milburn. 

In the dark face of the Moon, soon after crossing 

the northeast limb of the visible face from Earth, 

there is a prominent crater of 75 km in diameter, 

called Espin, the hunter of stars in the solitude of his 

small observatory of the distant Tow Law vicarage. 

A more extensive biography of Espin was published 

by us in the winter issue of 2011 of the Spanish 

magazine "El Observador de Estrellas Dobles” (OED) 

and can be downloaded for free from their website 

(Gonzalez Carballo, 2010). 

The Espin’s Neglected Doubles 

The result of such a long astronomical life is difficult 

to be summarized, but it’s enough to say that one 

of his spectroscopes, designed by himself, was able to 

observe all the stars of the Argelander’s charts below 

the 9th magnitude, and cataloged 3800 red stars. 

However, it is his contribution to the world of double 

stars which has attracted the attention of posterity, 

especially for us. 

Almost all of Espin’s double stars, despite their 

variety, have a difference in brightness between the 

components rather striking, though, as noted by 

Comellas (1988), Espin used to exaggerate the real 

differences between them. The secondary components 

are almost always brighter than recorded. Their positions 

are quite accurate, proof of his expertise in the 

management of graduated circles. 

In his publications he cataloged 2574 new double 

stars, plus another 912 that Milburn added after his 

death, a total of 3487. In the WDS there are 3135 

stars with his designation (ES), of which a total of 429 

(12.3%) are considered neglected, according to the list 

made for us by Brian Mason. 

Today, a few decades after his death, he still appears 

in the "Top Ten" of the WDS as one of the most 

active observers. 

The distribution of the Espin’s double stars in the 

sky is fairly concentrated in constellations that culminate 

between summer and autumn, which is not surprising 

when you consider the harsh winters of the 

English east coast in that latitude, and the common 

weather conditions in Great Britain. In fact, seven

Vol. 8 No. 2 April 1, 2012 


Page 100 


35 

30 

25 

20 

15 

10 

5 

31,6 

20,8 

10,2 

8,4 

7,4 

5,3 

5,6 

4 3,2 

3,5 

40 

35 

30 

25 

20 

15 

10 

5 

33,7 

28,6 

15,5 

9,1 

5,5 

3,5 

2,5 1,9 

0 

AND AUR CAS CYG DRA HER LAC LYR PEG OTHER 

0 

Vol. 8 No. 2 April 1, 2012 


Page 101 


to capture all Espin’s systems components. However, 

in some cases, especially due to the high ΔM of some 

systems, I worked with lower exposures, 1 second or 

less, to prevent saturation them and obtain higher 

quality astrometry and photometry. All images were 

treated with the corresponding dark-frames. 

I used MaxIm DL (from Diffraction Limited) for 

imaging and CCD camera control software. 

These images were averaged in groups of 8 with 

Astroart 3.0 software performing a manual stack that 

allowed me to eliminate those that have poor quality 

due to turbulence or poor guiding; in this way, I finally 

obtained 5 master images with a better signal/ 

noise relation (SNR). These five master images can be 

averaged again to get even a better quality one. Thus, 

I have for every system a total of 6 high quality images 

with an excellent SNR for all the measures I 

made. 

The astrometric reduction was carried out by software 

developed by Herbet Raab, Astrometrica 

(version 4.6) using UCAC3 catalog which usually 

yields residual differences of less than 0.1”. After obtaining 

the absolute astrometry of our stars in these 6 

images, I proceeded to calculate theta (angle position) 

and rho (angular separation) with the application created 

by Julio Castellano, Dobles. 

In addition, Astrometrica also calculated the resolution 

per pixel and the orientation of the image, both 

necessary in order to perform measurements with the 

Reduc software, the impressive software developed by 

our French friend and colleague Florent Losse. I used 

version 4.6. This method was used with closesr pairs 

(generally, 2.5” or less). In these cases, Reduc turned 

out to be a fundamental tool. 

However, when possible, every system was measured 

using both types of software, so the data presented 

here are the average of both measures. Only 

those closer pairs have been measured exclusively 

with Reduc by their best reliability. 

In the Notes section that accompanies the Table 

of measurements, I have indicated the absolute astrometry 

of the A component star (calculated with 

Astrometrica) in case the WDS Catalog has an error 

of identification or position of some of the systems. 

The Measures 

In Table 1 I present the measures of the first 100 

Espin’s neglected double stars. I also included six 

new discoveries of systems that were found in the vicinity 

of some of the studied doubles or, in two cases, 

there are new components of some of them. 

The images were taken between November 3, 

2010 and July 8, 2011. In Table 10 I present a selection 

of the most of the Espin’s observed pairs. These 

are cuts from the images in fit format (200x200 pixels 

of the original). 

The data structure in the table (from left to right) 

is as follows: 

- Column 1: WDS catalog Identifier. They are 

listed in order of increasing right ascension. If the 

double of one line is a new discovery it will show the 

name "uncat"; in this cases I haven’t scored any identifier 

in the hope that will assigned by the USNO. If 

it is a new component of an Espin’s system we use the 

same identifier of the WDS. In all these cases, the 

exact coordinates (J2000) can be found in the 

"Discoveries" section. 

- Column 2: Name of the system. If the double of 

that line is a new discovery, I have maintained the 

traditional nomenclature of the WDS, employing the 

observer code that the author has in the catalog 

(CRB). 

- Columns 3 and 4: Magnitudes for each component, 

given in WDS catalog. In the case of new doubles 

it has proceeded to annotate (in cursive boldface) 

other one proceeding from other sources. For more 

details, see the section “Discoveries”. 

- Column 5: The epoch of the observation, given 

in fractional Besselian year. 

- Column 6: Position Angle (in degrees). 

- Column 7: Angular Separation (in arcsec). 

- Column 8: Number of nights. 

- Column 9: Notes.

Vol. 8 No. 2 April 1, 2012 


Page 102 


Table 1: Relative Astrometry of the Observed Pairs 

WDS Id. Discoverer WDS Mags. Epoch 

Theta 

(deg) 

Rho 

(a.s.) 

Nights 

Notes 

00078+4507 ES 1357 9.91 14.70 2011.510 181.5 4.261 2 1 

uncat 

CRB 2AC 9.91 12.01 2011.510 225.9 54.65 2 2 

00078+4507 

00287+5040 ES 1128 11.31 12.50 2010.861 178.5 2.87 1 3 

00304+3743 ES 2545 10.60 11.1 2010.861 86.8 9.846 1 4 

00401+3541 ES 2080 9.47 14.00 2010.861 44.4 4.901 1 5 

00526+3100 ES 2364 9.89 12.80 2010.880 135.4 5.976 1 6 

01393+4901 ES 1132 10.30 12.70 2010.861 214.4 6.08 1 7 

02164+3628 ES 270BC 11.29 13.50 2010.842 356.9 2.92 1 8 

02348+4924 ES 458AC 10.23 14.60 2010.861 244.0 20.67 1 9 

02497+3721 ES 2553 9.30 10.80 2010.864 177.1 6.567 1 10 

02564+3716 ES 2146AC 12.47 12.80 2010.864 101.4 8.82 1 11 

03276+5520 ES 875 10.91 12.00 2010.864 306.5 10.208 1 12 

03401+6310 ES 1881 11.95 12 2010.880 158.1 2.688 1 13 

03442+3710 ES 2560 10.50 12.00 2010.864 287.2 8.857 1 14 

03592+6013 ES 1778 9.40 12.20 2010.880 162.6 3.787 1 15 

04016+6126 ES 1959 10.5 12.2 2010.880 21.0 3.036 1 16 

04095+5257 ES 1067 10.57 13.20 2010.880 44.9 4.873 1 17 

04357+3800 ES 2562AB 11.70 12.40 2010.864 355.9 30.947 1 18 

04572+4322 ES 1527AC 10.39 12.80 2010.864 319.5 11.50 1 19 

05197+3421 ES 2466 11.59 14.30 2010.864 303.7 7.505 1 20 

uncat CRB 3 15.49 15.60 2010.864 122.5 50.81 1 21 

05213+5113 ES 959 11.64 14.10 2010.864 172.1 4.444 1 22 

05225+4621 ES 1231AC 10.40 11.40 2010.864 18.4 17.413 1 23 

05328+6359 ES 1886 10.02 12.20 2010.880 35.5 10.236 1 24 

05469+4250 ES 1626 10.66 13.10 2010.864 262.1 8.20 1 25 

05598+4752 ES 1232AB 11.50 12.70 2010.864 268.4 4.531 1 26 

05598+4752 ES 1232AC 11.50 11.80 2010.864 178.2 21.69 1 27 

06132+4124 ES 1730 10.33 14.80 2011.118 

104.5 

1 

5.96 1 28 

06194+3718 ES 287 9.81 13.3 2011.118 257.6 5.945 1 29 

06381+5227 ES 1075 10.36 13.00 2010.864 4.9 8.131 1 30 

06435+3929 ES 2098BC 10.64 13.30 2011.118 315.6 3.56 1 31 

06595+3706 ES 2621AH 7.88 12.0 2011.118 119.2 9.496 1 32 

07080+4650 ES 1240AC 10.31 14.90 2011.118 296.4 17.63 1 

33, 

34 

07148+5142 ES 1081AB 10.13 13.30 2011.118 205.6 5.473 1 35 

Table 1 continues on next page.

Vol. 8 No. 2 April 1, 2012 


Page 103 


Table 1 (continued) : Relative Astrometry of the Observed Pairs 


Theta 

(deg) 

Rho 

(a.s.) 

Nights 

Notes 

07234+3510 ES 418 8.40 13.60 2011.118 23.9 13.963 1 36 

07453+4041 ES 1537 10.68 14.60 2011.091 354.8 10.934 1 37 

07566+5017 ES 905 10.72 13.40 2011.091 290.6 5.383 1 38 

08085+5130 ES 70BC 12.90 13.40 2011.151 343.5 7.673 1 39 

08225+6318 ES 1899 9.44 11.10 2011.091 219.8 12.884 1 40 

17374+5040 ES 2661BC 9.84 12.80 2011.516 17.9 14.71 1 

18218+6358 ES 1837 9.83 11.60 2011.516 216.9 14.79 1 41 

18227+3522 ES 2172 12.17 13.20 2011.516 46.6 2.861 1 

18296+4851 ES 2667 10.64 14.70 2011.516 67.5 13.57 1 42 

uncat 

CRB 4BC 14.70 ~14.95 2011.516 290.2 3.10 1 43 

18296+4851 

18334+3727 ES 2481 10.50 11 NOT FOUND 44 

18343+3200 ES 2420AB 11.74 11.7 2011.516 133.9 2.925 1 

18451+3756 ES 2020 10.33 12 2011.510 342.1 3.662 1 45 

18466+3853 ES 2021AC 10.26 13.40 2011.516 260.4 23.03 1 

18493+3301 ES 2287 10.90 12.30 2011.516 293.1 3.873 1 

18517+6222 ES 1841 10.81 13.30 2011.515 105.1 3.419 1 

18523+3321 ES 2233BC 11.90 12.10 2011.516 88.0 2.819 1 

18555+4411 ES 1428BC 13.50 13.70 2011.510 119.9 2.613 1 46 

18572+3704 ES 2030AB 11.20 14.20 2011.516 234.4 2.948 1 

18590+3654 ES 2032 10.75 13.60 2011.516 247.0 41.41 1 

19057+6502 ES 1914 10.50 11.50 2011.515 338.3 2.594 1 

19238+4021 ES 1662 10.60 12.40 2011.510 72.81 3.17 1 47 

19252+4340 ES 1432CD 13.10 13.50 2011.423 258.2 5.6495 1 48 

19270+4129 ES 1663AB 8.75 13.10 2011.513 212.5 9.57 1 49 

19275+5005 ES 1096 10.15 12.60 2011.513 159.1 6.82 1 50 

19296+3453 ES 2240AC 12.30 12.80 2011.513 156.4 2.822 1 

19304+3200 ES 2369 9.93 13.70 2011.513 65.9 7.95 1 51 

19310+3507 ES 2241AB 10.20 12.20 2011.510 297.4 28.38 1 52 

19310+3507 ES 2241BC 12.60 12.90 2011.510 22.4 2.813 1 53 

19310+3507 ES 2241BD 12.60 14.10 2011.510 342.8 8.629 1 54 

19348+5510 ES 655BC 11.30 12.80 2011.510 59.9 2.952 1 55 

19364+4808 ES 491AB 10.15 10.60 2011.477 53.51 9.989 1 56 

19374+4619 ES 656AC 10.50 11.20 2011.423 292.1 38.36 1 57 

19374+4619 ES 656CD 11.20 11.50 2011.423 242.2 2.744 1 58 

19376+4023 ES 1666 10.59 13.30 2011.513 309.6 4.021 1 

19386+4020 ES 1668 11.18 12.20 2011.510 140.5 2.812 1 59 

19422+4413 ES 1435 9.93 13.70 2011.513 124.3 4.134 1 

Table 1 continues on next page.

Vol. 8 No. 2 April 1, 2012 


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Table 1 (continued) : Relative Astrometry of the Observed Pairs 


Theta 

(deg) 

Rho 

(a.s.) 

Nights 

Notes 

19476+6403 ES 1917 8.40 12.50 2011.513 338.3 8.04 1 

19477+3531 ES 2244 10.32 13.20 2011.513 24.8 2.75 1 

19484+3144 ES 354 8.96 11.90 2011.510 332.9 9.72 1 

19492+4238 ES 1565BC 12.60 13.70 2011.510 49.8 4.571 1 60 

19495+3843 ES 84AB 6.11 11.10 2011.513 161.2 10.14 1 

19495+3843 ES 84AC 6.11 13.2 2011.513 93.7 21.58 1 

19495+3843 ES 84BC 11.10 13.2 2011.513 65.8 20.02 1 

19500+4509 ES 23AC 8.27 15 2011.513 97.5 12.99 1 61 

uncat CRB 5 17.79 17.79 2011.516 289.9 3.611 - 62 

19500+3243 ES 2371CD 12.00 13.00 2011.513 178.6 2.874 1 63 

19501+3158 ES 2427AB 10.70 12.40 2011.477 50.4 15.56 1 64 

19514+1929 ES 2114 9.38 13.10 2011.513 223.1 12.71 1 65 

19521+3148 ES 2428AB 8.60 11.10 2011.513 90.1 89.18 1 66 

19522+3449 ES 2300 9.88 12.80 2011.513 251.1 5.27 1 

19548+3724 ES 2118AB 9.83 13.80 2011.513 274.9 10.53 1 

19566+6122 ES 1851 10.47 12.70 2011.513 154.8 6.19 2 67 

20039+4411 ES 85AD 12.5 10.52 2011.513 306.6 11.152 1 68 

20097+6220 ES 1853 12.06 12.10 2011.513 293.7 4.43 1 69 

20142+4744 ES 799AB 10.98 11.10 2011.513 17.0 2.066 2 70 

20142+4744 ES 799CD 11.30 15.70 2011.513 73.4 4.3995 2 71 

20362+3812 ES 2511 11.62 11.80 2011.478 250.9 7.147 1 72 

uncat CRB 6 16.16 16.30 2011.510 155.9 10.85 1 73 

20461+3653 ES 2514 10 11 2011.510 101.1 2.894 1 74 

21221+3525 ES 2259 9.43 11.40 2011.510 244.9 4.42 1 75 

21231+3647 ES 2124 10.35 11.90 2011.423 263.6 7.7305 1 76 

21254+4848 ES 1102BC 12.30 13 2011.510 36.3 6.789 1 77 

21254+4818 ES 1102CD 13 13.80 2011.510 109.5 3.602 1 78 

uncat 

CRB 7Ca,Cb - - 2011.622 109.5 1.62 1 79 

21254+4818 

21268+3337 ES 2382 12.49 13.80 2011.510 256.7 7.73 1 80 

21278+3636 ES 2127 10.36 10.60 2011.510 298.3 4.199 1 81 

21526+5013 ES 1175 11.16 12.60 2011.511 210.8 9.69 1 82 

23021+4451 ES 1349 8.93 13.70 2010.861 173.0 3.93 1 83 

23033+4904 ES 856 9.79 12.50 2010.861 6.7 7.38 1 84 

23086+3620 ES 2078 10.44 13.40 2010.861 2.1 4.03 1 85 

23210+3709 ES 2001 10.89 12.20 2010.861 296.7 8.17 1 86 

Table 1 notes on next page.

Vol. 8 No. 2 April 1, 2012 


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Notes 

1. ES 1357. In And. Only measured in 1915 by Espin. 

Rho decreasing and theta increasing significantly 

due to the pM of A-component: 37.84/-3.65 

(PPMXL). I see a new component with the same pM 

at 54.646”. See note below. 

2. CRB 2AC. In And. New CPM pair, see “Discoveries” 

section. 

3. ES 1128. In And. Only measured in 1912. Proper 

motion of A = 1.65/-1.15 (PPMXL). Rho decreasing. 

4. ES 2545. In And. Only measured in 1932. Erroneous 

theta in Espin measure (+180 degrees). A 

componet has high proper motion: 27.2/-20.7 

(PPMXL). Geat dM (3.40). The brigthness of B component 

is substantially weaker than what is noted 

in WDS. 

5. ES 2080. In And. Only measured in 1924 by Espin. 

Theta decreasing. Difficult: great dM (4.3). 

6. ES 2364. In Psc. Only measured in 1929 by Espin. 

High dM (3.89). Rho decreasing, theta increasing. 

Proper motion of A-component: 1.2/-6.8 (PPMXL). 

7. ES 1132. In And. Only measured in 1912. Poper 

motion of A = 29.2/1.6 (PPMXL). Rho remains. 

Theta increasing. 

8. ES 270BC. In And. Two measures in WDS (1924 

and 1926). Theta and rho remains. Proper motion 

of A = -0.2/-7.2 (PPMXL). 

9. ES 458AC. In And. Only measured in 1907. Theta 

remais. Rho decreasing. Icompatible proper motions: 

A = 1.8/-8.4 and C = -19.3/-15.3 (PPMXL) . 

I see brighter component B as indicated in WDS. 

10. ES 2553. In Per. Only measured in 1932 by Espin. 

Correct coordinates: A=02 49 45.86 +37 21 18.5 

and B=02 49 45.90 +37 21 12.5 High dM (2.96). 

11. ES 2146AC. In Per. Two measures in WDS (1925 

and 1980). Rho decreasing and theta increasing. A 

very beautiful trio of closed stars (see image 7, 

table 8). The RGB composite image of Aladin (from 

POSSI and POSSII images) suggests that only A- 

component has pM (-27.4/-73.6, according to 

PPMXL). 

12. ES 875. In Per. Only measured in 1910 by Espin. 

Theta and rho increasing. 

13. ES 1881. In Cam. Two measures in WDS (1921 and 

1978). 1978 measurement change A for B in theta 

value. I also see brighter B component. Rho decreasing. 

Proper motion of A-component is - 

7.8/7.8. Beautiful and delicate couple. I see them 

weaker than WDS magnitudes. 

14. ES 2560. In Per. Only measured by Espin in 1932. 

Rho increasing, theta decreasing. A-component 

has pM = 31.4/32.5 (UCAC3 and PPMXL). 

15. ES 1778. Only measured in 1919 by Espin. Marked 

in WDS as “Dubious double” (X). I found it at this 

coordinates: A=035818.45 +60 12 31.0 and B=03 

58 18.56 +60 12 28.1. Rho decreasing. High dM 

(3.36). Small and incompatible proper motions, 

according to PPMXL (A=-8.6/2.8 and B=-10.8/- 

8.2). 

16. ES 1959. In Cam. Two measures in WDS (1922 and 

1983). Theta decreasing. Proper motion of 

A=11.7/12.4 (PPMXL). dM=2.36. 

17. ES 1067. In Cam. Only measured in 1911 by Espin. 

Stable couple. Wrong position in WDS. Correct coordinates: 

A=04 09 20.50 +52 51 57.1 (TYC 3718 

-1508-1) and B=04 09 20.88 +52 52 00.6. 

18. ES 2560. Two measures in WDS (1932 and 1985). 

My measurements are agree better with Espin annotations 

than with the latest. Stable couple. 

19. ES 1527AC. In Aur. Only two measures in WDS 

(1916 and 1983). The 1983 measure confused the 

Espin couple with other two near stars (04 57 

22.229 +43 22 40.8). Espin’s couple remains stable. 

Incompatible pM (A=1.6/-7.7 and B=-11/- 

7.3, according to PPMXL). AB is neglected too. 

20. ES 2466. In Aur. Only measured in 1931 by Espin. 

Spect. A = A2. Rho increasing, theta slowly decreasing. 

High dM (2.73). Correct coordinates: 05 

19 44.68 +34 25 05.35. 

21. CRB 3. In Aur. New CPM. Magnitudes from 

GSC2.3. See “Discoveries” section. 

22. ES 959. In Aur. Only measured by Espin in 1910. 

Theta and rho slowly increasing. Great dM (2.49). 

High pM of A-component according to UCAC3 and 

PPMXL (0.7/-96.9). The RGB composite image of 

Aladin (from POSSI and POSSII images) suggests 

that only A-component has this high pM. Correct 

coordinates of A = 05 21 15.326 +41 11 08.10 

(UCAC3). 

23. ES 1231AC. In Aur. Only measured by Espin in 

1913. Theta and rho increasing. A-component has 

significant pM: -35.9/-36.9 (PPMXL) and it’s incompatible 

with B pM (10.7/3.5, according to 

PPMXL). 

24. ES 1886. In Cam. Only measured by Espin in 1921. 

High dM (3.23). A-component has high pM (-12/- 

66) and that explains the difference of the values 

in Ap and Sep that I have obtained. Rho increasing, 

theta decreasing. 

25. ES 1626. In Aur. Rho increasing and theta slowly 

decreasing. Only two measures in WDS. Proper 

motion of A-component is 5.7/-13.1 (PPMXL). 

26. ES 1232AB. In Aur. Theta and rho increasing. A- 

component’s pM is substantially different what is 

noted in WDS: 49.8/-12.1 (PPMXL). AC pair is neglected 

too (see note #27). 

27. ES 1232AC. In Aur. Rho increasing, theta decreasing. 

Incompatible proper motions (A=49.8/-12.1 

an B=-5.5/5.4). AB pair is neglected too (see note 

#26).

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28. ES 1730. In Aur. Only measured in 1918 by Espin. 

Rho increasing, theta decreasing. Difficult: high dM 

(4.62). Small pM in both components. 

29. ES 287. In Aur. Only measured by Espin in 1906. 

Stable pair. The high pM of A-component (-.25/- 

43.8, PPMXL) indicates than ES 287 must be CPM, 

although pM of B-component not appears in catalogues 

(UCAC3 or PPMXL). The RGB composition 

image of Aladin (POSSI and POSSII) suggested it 

too. 

30. ES 1075. In Aur. Theta decreasing and rho increasing. 

Two measures in WDS (1911 and 1925). Incompatible 

proper motions according to PPMXL 

data (A=-17.6/-37.3 and B=-9.5/-2.3). High dM 

(2.92). 

31. ES 2098BC. In Aur. Only measurement in WDS 

(Espin, 1924). Rho decreasing, theta increasing. 

Discrepant values of A-component pM in UCAC3 

and PPMXL, in any case bigger than it is indicated 

in WDS. 

32. ES 2621AH. In Aur. Only measured by Espin in 

1892. High dM (4.89). Discrepant values between 

my measurement and what Espin measured in 

1892. No significant proper motion in any component. 

The system appears very clearly in the images 

so, probably, it is an error in the Espin annotations. 

33. ES 1240AC. In Lyn. A-component has high proper 

motion (95/-8 in WDS). That explains the substantial 

difference in theta and rho values since the 

first measurements of Espin (in 1913). Rho increasing, 

theta decreasing. High dM (4.27). 

34. ES 1240AB. In Lyn. Not measured because A- 

component (with high pM, see note above) is actually 

just on the B-component. 

35. ES 1081AB. In Lyn. Only measured by Espin in 

1911. Theta and rho increasing. Small pM of both 

components. High dM (3.38). 

36. ES 418. In Gem. Only measured in 1907 by Espin. 

Theta increasing. High dM (6.01). 

37. ES 1537. In Lyn. Only one measurement in WDS 

(1916, Espin). Rho increasing, probably due to high 

pM of A-component (7/-49 in WDS). High dM 

(3.21). 

38. ES 905. In Lyn. Only one measurement in WDS 

(1910, Espin). Theta and rho increasing. Incorrect 

coordinates in WDS, the real Espin double is a near 

couple located 1.5’ at East. Coordinates of A = 07 

56 44.29 +50 18 00.0 and B = 07 56 43.79 +50 

18 01.9. 

39. ES 70BC . In Lyn. Two measurements made by 

own Espin in WDS (1901 and 1926). While rho is 

stable, theta has substantially increasing between 

the measurements of 1901 and 1926, probably 

due to an annotation error (248º instead of 348º). 

Not seen significant pM in any of the components. 

40. ES 1899. In UMa. Two measurements in WDS (1913 

and 1934). Rho and theta increasing due to A- 

component pM = 13.5/-24.9 (PPMXL). High dM 

(3.52). 

41. ES 1837. In Dra. Only one measurement in WDS 

(1920, Espin). Values of theta and rho had change 

substantially since 1920 due to the high proper 

motion of A-component: 19.2/118.4 (PPMXL) See 

Figure 6. 

Figure 6: High pM of A-component of ES 1837 (DSSI/DSSII 

RGB Aladin) 

42. ES 2667. In Dra. Theta and rho increasing due to 

pM of B-component as it can be seen in the RGB 

composition image of Aladin (see note below). 

43. CRB 4BC. In Dra. New component of ES 2267 system, 

see “Discoveries” section. 

44. ES 2481. In Lyr. Not found in the coordinates or 

near them. Marked in WDS as X “Dubious Double”. 

WDS Notes: “Not found by Heintz at IDS position” 

(Hei1985a). 

45. ES 2020. In Lyr. Two measurements in WDS (1923 

and 1940). Rho increasing and theta decreasing. 

pM of A-component = 19/-24. Difficult: dM = 2.8. 

46. ES 1428BC. In Lyr. Two measurements in WDS 

(1897 and 1964). Theta and rho decreasing. Beautiful 

couple, delicate. 

47. ES 1662. In Lyr. One measurement in WDS (1917, 

Espin). Precise coordinates for A = 19 23 48.40 

+40 20 36.0. Proper motion of A-component = - 

9.4/-17.7. Difficult: dM = 2.19. 

48. ES 1432CD. In Lyr. Rho increasing, theta decreasing. 

Only one measurement in WDS (1915, Espin). 

No appreciate pM, small dM (0.49), very delicate 

couple. 

49. ES 1663AB. In Lyr. One measurement in WDS

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(1917, Espin). Theta decreasing, rho increasing 

substantially due to pM of A-component (2.5/16.9 

according to PPMXL). 

50. ES 1096. In Cyg. Only measured in 1911 by Espin. 

Rho decreasing slowly and theta increasing. 

51. ES 2369. In Cyg. Only one measurement in WDS 

(1929, Espin). Theta decreasing due to high proper 

motion of A-component (-3/-59, WDS). 

52. ES 2241AB. In Cyg. Incorrect coordinates in WDS. 

Precise coordinates: A=19 31 41.50 +35 09 37.7 

and B=19 31 39.46 +35 09 50.7. Insignificant 

proper motions. Stable pair. Components BC y BD, 

see in notes #53 and #54. 

53. ES 2241BC. In Cyg. Precise coordinates: B=19 31 

39.46 +35 09 50.7 and C=19 31 35.90 +35 09 

52.4. Delicate pair, small dM (0.81). Theta and rho 

decreasing slowly. 

54. ES 2241BD. In Cyg. Precise coordinates: B=19 31 

39.46 +35 09 50.7 and D=19 31 39.26 +35 09 

59.2. Theta and rho decreasing. 

55. ES 655BC. In Cyg. Only one measurement in WDS 

(1908, Espin). Stable pair. Insignificant pM. 

56. ES 491AB. In Cyg. One measurement in WDS 

(1907, Espin). Stable pair. Incorrect coordinates in 

WDS; the correct for de A-component are: 19 36 

39.41 +47 58 59.5. Incompatible proper motion. 

Optical pair. 

57. ES 656AC. In Cyg. Only measured in 1908 by 

Espin. Stable pair. Small pM in both components. 

AB pair is HJ 1427. Incorrect coordinates in WDS 

(A=19 37 25.24 +46 18 37.6). 

58. ES 656CD. In Cyg. Stable couple. Only measured in 

1908 by Espin. dM is bigger than what WDS indicates 

(1.77). 

59. ES 1668. In Cyg. Two measurements in WDS (1917 

and 1936). dM=0.77. pM A-component = -11/4. 

60. ES 1565BC. In Cyg. Only one measurement in WDS 

(1916, Espin). Rho increasing, probably due to pM 

of A-component (-29/-29 in WDS). Small dM 

(0.33). Beautiful pair. 

61. ES 23AC. In Cyg. One measurement in WDS 

(1915, Espin). Rho increasing, theta decreasing. 

Great dM (5.6). Proper motion A-component = - 

7.9/-8.4 (PPMXL). Near I found a new quick CPM 

pair (see note below). 

62. CRB 5. In Cyg. New CPM near ES 23AC. See 

“Discoveries” section. 

63. ES 2371CD. In Cyg. Two measurements in WDS 

(1929 and 1988). The 1988 measurement is inconsistent 

with the observations of Espin and myself, 

especially in rho. Theta increasing. 

64. ES 2427AB. In Cyg. Two measures in WDS (1930 

and 1933). Great increment of theta and rho values 

due to high proper motion of A-component (- 

124/-126 in WDS, -110/-130.7 in PPMXL). 

65. ES 2114. In Cyg. Two Espin’s measurements (1924 

and 1929). I observe distinctly less bright the A- 

component. Rho increasing substantially due to 

high proper motion of A, according to PPMXL is - 

60/-92.3 (-38/-78 in WDS). 

66. ES 2428AB. In Cyg. There is a tiny star near A- 

component separated by 9”. Stable couple. 

67. ES 1851. In Dra. One measurement in WDS (1920, 

Espin). Theta and rho increasing due to pM of A- 

component (5/40, WDS). 

68. ES 85AD. In Cyg. One measurement is WDS 

(1907, Espin). Theta and rho decreasing. WDS 

don’t publish the magnitude of D-component. According 

to GSC2.3 Vmag is 14.45. Proper motion 

of A=-2/-3 (WDS) and D=-7.8/-4.0 (PPMXL). 

69. ES 1853. Two measurements in WDS (1911 and 

1977). Theta decreasing slowly. Very delicate pair, 

dM = 0.11. 

70. ES 799AB. In Cyg. Only one measurement in WDS 

(1909). Rho decreasing, theta increasing. Very 

closed and equilibrated pair, small dM (0.17). 

71. ES 799CD. In Cyg. High dM (3.31). Insignificant 

pM. Only measured in 1909. 


(1931, Espin). Incorrect coordinates in WDS; the 

correct for A-component is: 20 36 08.27 +38 12 

05.9. Rho increasing, theta decreasing. dM = 0.5. 

Insignificant pM. 

73. CRB 6. In Cyg. New CPM pair near ES 2514 , see 

“New Discoveries” section. 

74. ES 2514. In Cyg. Only one measurenment in WDS 

(1931, Espin). Rho decreasing, theta increasing. 

Small dM = 0.55. 


(1926, Espin). Theta decreasing slowly. Proper motion 

of A-component = 22/-8. 


(1924, Espin). Incorrect coordinates in WDS. Correct 

are: A=21 23 15.49 +36 46 39.9. 

77. ES 1102BC. In Cyg. Two measurements in WDS 

(1900 and 1911). Rho increasing and theta decreasing. 

Small dM (0.33). I observe a faint star 

near C-component. See below (note #77). 

78. ES 1102CD. In Cyg. Only measured in 1911 by 

Espin. Stable pair. dM = 1.21. 

79. CRB 7Ca,Cb. In Cyg. New component of ES 1102 

system, near the B star, see “Discoveries” section. 


(1929, Espin). Marked in WDS as I (Identification 

uncertain). I see it in the position indicated in WDS. 

Theta and rho increasing due to proper motion of 

the components: A = 13/-17.9 and B = -71/32.9. 

Incompatible pM. Optical pair. See Figure 7. 

81. ES 2127. In Cyg. One measurement in WDS (1924, 

Espin). Insignificant pM of A-component. Rho de-

Vol. 8 No. 2 April 1, 2012 


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same spectral class (A = F7V/F8III, C = G4V/F9III, 

Table 3), although it has not been determined 

whether it is a giant red or a dwarf star. After consultation 

with Francisco M. Rica Romero through a private 

communication states that we can not conclude, 

with current data, whether it is a physical or an optical 

pair. This new pair will be further explored to try 

to get definitive results. 

Figure 7: DSS-POSS I, DSS-POSSII and RGB composition images 

of ES 2383 (Aladin). 

creasing slowly. 

82. ES 1175. In Cyg. Only measured by Espin un 1912. 

Theta and rho increasing. 

83. ES 1349. In And. Only measured in 1914. Rho 

decreasing, theta increasing. Spec. A = F0. Proper 

motion of A = 4.3/2.2. 

84. ES 856. In And. Only measured in 1909. Rho 

slowly increasing, theta slowly decreasing. Propor 

motion of A-component = 20/4.2 (PPMXL). 

85. ES 2078. In And. Only two measures in WDS (1923 

and 1933). A-component has a substantial proper 

motion: -50.6/-4.2 (PPMXL). This explains the 

large decrease in rho and the striking increase of 

theta. 

86. ES 2001. In And. Two measures in WDS (1922 and 

1935). Rho and theta increasing. Proper motion of 

A = 15.8/-8.3 (PPMXL). 

Table 2: Proper motions of the new system 

CRB 2AC (PPMXL). 

pM AR 

pM Dec 

A 37.84 -3.65 

C 35.41 -3.77 

Table 3: JHK Photometry (2MASS). 

J H K 

A 8.754 8.532 8.490 

C 10.734 10.449 10.420 

Discoveries 

Six new double stars have been found. None of 

them has been published in any consulted source. 

Two of them are new close components of systems 

catalogud by Espin, whereas the other four are unpublished 

doubles located in the vicinity of other 

Espin’s double stars; all four cases appear to be new 

common proper motion pairs. 

CRB 2AC 

New component of the system ES 1357 (in Andromeda). 

It is situated at the following coordinates: 

00 07 41.90 +45 07 06.9 

This is a star of magnitude V = 12.01 based on 

photometry from the catalogs and UCAC3 and 

CMC14. It is placed at 54.65" and 225.9° of the A 

component, Figure 8. It has a very similar proper motion 

to the A star of the system (see Table 2), and the 

Figure 8: CRB 

del Viento”. 

2AC obtained at the “Observatorio Cerro

Vol. 8 No. 2 April 1, 2012 


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CRB 3 

A new pair with common proper motion located in 

Auriga, in the vicinity of the system ES 2466 (Figure 

9). They have a high common proper motion (see Table 

4) and a compatible spectral class (A = M2.5/K4III 

and B = M3V/K4III), calculated using the method developed 

by Francisco M. Rica Romero from JHK photometry 

of 2MASS (Table 5). Given the impossibility 

of obtaining UCAC3 photometry that allows us the 

extrapolation of the V magnitude, based on the Pavlov’s 

equations (Pavlov, 2009), we took the one offered 

by GSC2.3, resulting the following V magnitudes: A = 

15.49, B = 15.60. The separation of both components 

is 50.81" and they are situated at 122.5° of angular 

position. These two faint stars exceed the 15th magnitude 

(see Table 4) and their exact coordinates are: 

A = 05 19 34.22 +34 20 36.0 

B = 05 19 37.68 +34 20 08.7 


CRB 3 (PPMXL). 

pM AR 

pM Dec 

A 75.5 -213.9 

B 67.7 -209.5 

Figure 9: RGB composition image of the zone of ES 2466 and 

CRB 3 (Aladin). 

CRB 4 

This is a new component of the system ES 2667 

(in Draco). The B component of this Espin double is 

actually two close stars and with similar magnitude 

(Figure 10). They are located at the following coordinates: 

B = 18 29 36.834 +48 51 36.52 

C = 18 29 36.538 +48 51 37.59 


J H K 

A 11.759 11.164 10.918 

B 11.945 11.361 11.085 

Therefore, they are situated at 3.104" with a position 

angle of 290.2°. These stars do not appear as independent 

ones on professional catalogs. PPMXL only 

shows the proper motion (possibly combined) of a star 

in that position (122.3/44.6), but in view of the RGB 

composition of Aladin (DSSI and DSSII, Figure 11) it 

is clear that the two components move together. 

Probably it is a true physical double. It has not been 

possible to calculate the V magnitude for these stars 

because they don’t appear as independent in the 

2MASS catalog or elsewhere. However, we can obtain 

an approximation of the magnitude of the new component 

using the dM that resulted from the Reduc 

measurement of the system (dM=0.25) and the magnitude 

of the B component recorded in the WDS: 

14.70 + 0.25 = ~ 14.95.

Vol. 8 No. 2 April 1, 2012 


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CRB 5 

In the vicinity of the system ES 23AC I found a 

couple of stars that are moving rapidly in the same 

direction in view of the proper motions reflecting Simbad 

in the plates POSSI and POSSII from Aladin (see 

Figure 12). Given that the proper motion was so obvious 

I decided to dedicate some time researching the 

data I could obtain on the system. 

They are at the following coordinates: 

A = 19 50 18.288 +45 09 58.17 

(2MASS J195001828+4509581) 

B = 19 50 17.967 +45 09 59.44 

(2MASS J195001796+4509594) 

Figure 10: CCD image obtained by author with his 

usual equipment at the “Observatorio Cerro del Viento”. 

Unfortunately, these two stars are very faint. I 

could only find photometric references in GSC2.3 and 

CMC-14 catalogues which, however, only show the 

value of the A component: 17.79 (V) and 17.63 

(r'mag), respectively. It is quite probable that both 

measures reflect, in fact, the brightness of the two 

components together. In the absence of references in 

the UCAC3, I have found quite impossible to estimate 

the their V magnitudes. Therefore, and in a preliminary 

way, I decided to indicate in the Table 1 (column 

of magnitude values) the same magnitude for both 

components, using the value which appears for the A 

Figure 11: RGB composition from Aladin with DSSI and DSSII 

images showing the common proper motion of the B and C 

components of the system. 

Figure 12: Aladin image showing the POSSII plate of ES 

23 area and the localization of the new common proper 

motion pair.

Vol. 8 No. 2 April 1, 2012 


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CRB 2AC (Lepine&Shara, 2005) 

pM AR 

pM Dec 

A 47 138 

B 47 138 


images covering a time span of half a century, he corroborates 

these motions. 

All these data should be taken with caution until 

we develop a more detailed and conclusive study of 

this system that, is very possibly real binary system. 

In this regard, with the invaluable assistance of Francisco 

M. Rica Romero, I will conduct a thorough study 

of the new system in which we will obtain detailed 

images of the BVRI photometry with the IAC-80 telescope 

of the Instituto de Astrofisica de Canarias 

(IAC). 

CRB 6 

Near the system ES 2514 (in Cygnus), I found two 

relatively nearby stars that seemed to share a common 

proper motion. After consulting the PPMXL 

catalog, my intuition was confirmed by their having 

similar proper motion values (Table 8, Figure 14). 

They are located at the following coordinates: 

J H K 

A 15.205 14.568 14.306 

B 15.332 14.845 14.505 

A = 20 45 45.778 +36 58 20.14 

B = 20 45 45.370 +36 58 29.86 

They are separate, therefore, by 10.85" with a position 

angle of 155.9°. The GSC2.3 catalog shows a V 

magnitude for both components of 16.16 and 16.30, 

respectively. 

JHK photometry has shown identical spectral 

classes: A = M0.5V/K4III and B = M0.5V/K4III (Table 

9), and reinforcing the possibility that they may have 

a true physical nature. Anyway, like the previous one, 

it’s requires a more detailed and conclusive study to 

determine its exact nature. 

Figure 13: Cuts from POSSI (left) and POSSII (right) plates 

where it can be seen the faint components of this common 

proper motion pair. 

component in the GSC2.3 catalog. 

I believe that I found the JHK photometry of both 

components in the 2MASS and it can be seen in Table 

7. Using these data, I preliminarily calculated, following 

the methodology developed by Francisco M. Rica 

Romero, spectral classes that shows that both components 

are similar: A = M2.5V/K5III and B = M4V/ 

K4III. 

The data concerning proper motions are more illuminating. 

Fortunately, these two stars were measured 

in a much broader project that was developed 

some years ago (Lepine and Shara, 2005). In view of 

these data, which are those that are represented in 

red vectors of the Image 12 (Simbad), these two stars 

share a common proper motion (Table 6). However, it 

remains unpublished in the WDS or in the CCDM. 

Francisco M. Rica Romero has done an initial analysis 

to assess the quality of such measures, and, using 


CRB 6 (PPMXL). 

pM AR 

pM Dec 

A -48.7 -39.3 

B -54.4 -41.9 


J H K 

A 13.287 16.675 12.461 

B 13.029 12.435 12.213

Vol. 8 No. 2 April 1, 2012 


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CRB 7Ca,Cb 

This is a new component of the system ES 1102 

(in Cygnus). The component C proved to be a close 

couple. Their separation is almost in the limit of the 

resolution of the equipment I work with (Figure 15), 

so I contacted the well-known Madrilenian astrophotographer 

Miguel Angel Garcia , who operates a remote 

telescope of 35 cm at focal length of 2720 mm 

with a CCD STL1100 in OAR-SPAG observatory 

(Figure 17), located in the heart of Monfrague National 

Park (Cáceres). Responding to my call, he obtained 

a series of images using adaptive optics in 

which we could accurately measure those components 

and also obtain a beautiful view of the new system 

(Figure 16). Their separation is 1.62" at 109.5°. Given 

their closeness, the components do not appear resolved 

in the professional catalogs, making it quite 

impossible to calculate proper motions and magnitudes. 

The WDS indicates a magnitude = 13 for the C 

component. 

Figura 16: At the request of the author, this CCD image 

was obtained by Miguel Ángel García with his remotecontrolled 

observatory OAR-SPAG in Monfragüe National 

Park (Cáceres): 35 cm. telescope at 2720 mm. of 

focal distance. Here the Ca, Cb system is clearly resolved. 

Figure 15: CCD image of the system ES 1102 obtained by the 

author with his equipment (8” telescope at focal distance of 

1920 mm.). All the components of Espin’s system can be 

observed. The C star is also double (see Figure 16), as evidenced 

by its elongated shape. 

Figure 17: Remote Astronomical Observatory OAR-SPAG 

(Monfragüe) in which Miguel Ángel García (pictured) obtained 

the images that confirmed the presence of a faint star near 

the C component of ES 1102. 


Vol. 8 No. 2 April 1, 2012 


Page 113 


Table 10: A photographic atlas of selected Espin's doubles. 

1: ES 2545 2: ES 2364 3: ES 1132 

4: ES 270BC 5: ES 458AC 6: ES 2553 

7: ES 2146AC 8: ES 875 9: ES 1881 

10: ES 2560 11: ES 1778 12: ES 1067

Vol. 8 No. 2 April 1, 2012 


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13: ES 2562AB 14: ES 2466 15: ES 959 

16: ES 1231AC 17: ES 1866 18: ES 1626 

19: ES 1232AB AC 20: ES 1730 21: ES 287 

22: ES 1075 23: ES 2098BC 24: ES 2621AH

Vol. 8 No. 2 April 1, 2012 


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13: ES 2562AB 14: ES 2466 15: ES 959 

16: ES 1231AC 17: ES 1866 18: ES 1626 

19: ES 1232AB AC 20: ES 1730 21: ES 287 

22: ES 1075 23: ES 2098BC 24: ES 2621AH

Vol. 8 No. 2 April 1, 2012 


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25: 1240AC 26: ES 1081AC 27: ES 418 

28: ES 1537 29: ES 905 30: ES 70BC 

31: ES 1899 32: ES 2661BC 33: ES 1837 

34: ES 2172 35: ES 2420AB 36: ES 2020

Vol. 8 No. 2 April 1, 2012 


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37: ES 2021AC 38: ES 2287 39: ES 1841 

40: ES 2233BC 41: ES 1428BC 42: ES 2032 

43: ES 1914 44: ES 1662 45: ES 1432CD 

46: ES 1663AB 47: ES 2420AB 48: ES 2040AC

Vol. 8 No. 2 April 1, 2012 


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49: ES 2369 50: ES 2241AB BC BD 51: ES 655BC 

52: ES 491AB 53: ES 656AC CD 54: ES 1668 

55: ES 1435 56: ES 1917 57: ES 354 

58: ES 1565BC 59: 84AB AC BC 60: ES 23AC

Vol. 8 No. 2 April 1, 2012 


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61: ES 2371CD 62: ES 2427AB 63: ES 2114 

64: ES 2428AB 65: ES 2300 66: ES 2118AB 

67: ES 1851 68: ES 85AD 69: ES 1853 

70: ES 2511 71: ES 2514 72: ES 2259

Vol. 8 No. 2 April 1, 2012 


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73: ES 2124 74: ES 1102BC CD 75: ES 2127 

76: ES 856 77: ES 2078 78: ES 2001 



The author of this article would like to acknowledge 

the assistance provided all the time by the great 

Spanish specialist in double stars, my great friend 

and colleague, Rafael Benavides Palencia. In addition 

to his continuing assistance, his CCD camera has 

given, and continues to provide, an excellent service 

at the Observatorio Cerro del Viento. 

In the same way, I’d like to thank Francisco M. 

Rica Romero for his advice on certain astrophysical 

data without which it would have been impossible to 

reach certain conclusions about the systems studied. 

Likewise, I wish to thank Ignacio Novalbos Cantador 

for his advice and guidance while I was studying 

some systems. 

Also to Miguel Ángel García, from Observatorio 

OAR-SPAG (Monfragüe, Cáceres, Spain) for his help 

in obtaining images of the new system CRB 6Ca,Cb. 

Without them I would not have been able to determine 

the double nature of the C component of the system 

Es 1102. 

Of course, many thanks to Florent Losse for developing 

a software as powerful as Reduc. Without it 

many of the doubles here measured could not have 

been published. 

To Dr. Brian D. Mason, from the United States 

Naval Observatory, for giving me the list of neglected 

double stars of Thomas Espin. 

With regard to biographical and bibliographical 

information about Espin, I have been fortunate to 

have a number of privileged contacts that have 

helped me to be aware of a more detailed knowledge 

of our subject’s life. For this, I want to express my 

deepest gratitude to Mr. Simon Murray and Mr. 

David Hughes from the Newcastle Astronomical Society; 

to Professor F. Richard Stephenson and to Mrs. 

Pauline Russell, both from the University of Durham, 

for their graphic documents; to Mrs. Carol Harris, 

from the Library of that University, for their kind 

donation of a detailed and unpublished biography of

Vol. 8 No. 2 April 1, 2012 


Page 121 


Espin; and to Mr. Graham Espin for certain information 

published in some old English newspapers. 

Thank you very much for making easier my documentation 

of our beloved Thomas Espin. I hope this research, 

and the future ones I’ll write, serves to remember 

in the 21 st century the hard work that a 

humble vicar developed in the solitude of his observatory 

in the moorlands of Tow Law. 

I would also like to acknowledge the assistance of 

my colleagues, members of the Department of English 

Language of the I.E.S. Ciudad Jardín (Badajoz), when 

reviewing the English version of this work. Thanks 

Alfonso, Jane, María, Montaña and Reme. 

And, of course, to Guadalupe and Lucía for their 

infinite patience and understanding of a husband and 

father with his head always in the heavens. 

In this research I used Aladin and VizieR from 

CDS in Strasbourg, as well as the professional catalogs 

available through them. 

References 

AA.VV., 1992, The Stargazer of Tow Law (foreword by 

Patrick More). Published by Tow Law Local History 

Group. Durham. 

Bonnarel, F. et al, 2000, The ALADIN interactive sky 

atlas. A reference tool for identification of astronomical 

sources, Astron. Astrophys. Suppl. Ser. 

Vol. 143, Number 1, 33-40. 

Brown, A., 1974, The life and work of Revd. T. H. E. 

C. Espin, perpetual curate of Tow Law, with special 

reference to his astronomical research. Unpublished 

Thesis presented in the University of 

Durham. 

Castellano, J., 2006, Software “Dobles”. Available at: 

http://astrosurf.com/cometas-obs/ArtSoftUtil/ 

Software.html. 

Centre de Donées Astronomiques de Strasbourg, 1993 

-2011, Vizier Service. Available at : http:// 

webviz.u-strasbg.fr/viz-bin/VizieR. 

Centre de Donées Astronomiques de Strasbourg, 1999 

-2011, Aladin Sky Atlas. Available at : http:// 

aladin.u-strasbg.fr/. 

Comellas, J.L., 1988, Catálgo de estrellas dobles visuales. 

Ed. Equipo Sirius. Madrid. 

González Carballo, J. L., 2011, Espin: una vida de 

pasión astronómica, OED 6, 46-54. 

Lepine, S. and Shara, M. M., 2005, A catalog of northern 

stars with annual proper motions larger than 

02.15 (LSPM-NORTH catalog), Astron. J., 129, 

1483-1522. 

Losse F., 2001-2011, Reduc Software. Mailware available 

at: http://astrosurf.com/hfosaf/index.htm. 

Mason, B.D. et al., The Washington Double Star Catalog 

(WDS) 2006.5, U.S. Naval Observatory. 

Pavlov, H., 2009, Deriving a V magnitude from 

UCAC3, http://www.hristopavlov.net/Articles/ index.html 

Raab, H., 1993-2011, Software Astrometrica. Available 

at: http://www.astrometrica.at. 

Roeser, S. et al., 2008, PPMX Catalog of positions and 

proper motions, A&A, 488, 401. 

Zacharias, N. et al., 2010, The Third U.S. Naval Observatory 

CCD Astrograph Catalog (UCAC3), AJ 

139-2184. 

Juan-Luis G. Carballo is professor of Geography and History. His two great astronomical passions 

are double and variable stars. He observes from an urban observatory located in Badajoz, Spain, 

and is co-editor of the Spanish journal “El Observador de Estrellas Dobles” (OED). He maintains the 

blog “La Décima Esfera” (http://ladecimaesfera.blogspot.com), devoted to his astronomical works.

Vol. 8 No. 2 April 1, 2012 


Page 122 

Observations, Analysis, and Orbital Calculation 

of the Visual Double Star STTA 123 AB 

Nicholas J. Brashear 1 , Angel J. Camama 1 , Miles A. Drake 1 , Miranda E. Smith 1 , 

Jolyon M. Johnson 2 , Dave Arnold 3 , and Rebecca Chamberlain 1 . 

1. Evergreen State College, Olympia, Washington 

2. University of California, Chico 

3. Divinus Lux Observatory, Flagstaff, Arizona 

Abstract: As part of a research workshop at Pine Mountain Observatory, four students 

from Evergreen State College met with an instructor and an experienced double star observer 

to learn the methods used to measure double stars and to contribute observations to 

the Washington Double Star (WDS) Catalog. The students then observed and analyzed the 

visual double star STTA 123 AB with few past observations in the WDS Catalog to determine 

if it is optical or binary in nature. The separation of this double star was found to be 

69.9” and its position angle to be 148.0°. Using the spectral types, stellar parallaxes, and 

proper motion vectors of these two stars, the students determined that this double star is 

likely physically bound by gravity in a binary system. Johnson calculated a preliminary circular 

orbit for the system using Newton's version of Kepler's third law. The masses of the 

two stars were estimated based on their spectral types (F0) to be 1.4 M. Their separation 

was estimated to be 316 AU based on their distance from Earth (about 216.5 light years) 

and their orbital period was estimated to be 3357 years. Arnold compared the observations 

made by the students to what would be predicted by the orbit calculation. A discrepancy of 

14° was found in the position angle. The authors suggest that the orbit is both eccentric and 

inclined to our line of sight, making the observed position angle change less than predicted. 

Introduction 

This project was part of the 2010 Pine Mountain 

Observatory Summer Research Workshop. The students 

chose to study double stars because the concepts 

are relatively straight forward and they offer 

swift publication opportunities (Johnson 2008). Double 

star observations also have a long legacy, drawing 

from a large pool of individual contributors over 

the course of hundreds of years. The students from 

Evergreen State College—a school whose ethos is 

founded on cooperative learning—believed it was in 

their interest to participate in these ongoing collaborations. 

The aim of this project was three fold: to contribute 

observations of double stars to the Washington 

Double Star (WDS) Catalog, to learn the procedure 

for double star observation, and to study a dou- 

Figure 1: Left to right: Jo Johnson, Nick Brashear, Angel 

Camama, Miles Drake, Miranda Smith. The NexStar 6 SE 

telescope used in the project is in the center.

Vol. 8 No. 2 April 1, 2012 


Page 123 

Observations, Analysis, and Orbital Calculation of the Visual Double Star STTA 123 AB 

ble star to determine whether it is optical or binary. If 

the double star was found to be binary, the participants 

would calculate a rough orbit. 

The participants employed an equatorial-mounted 

Celestron NexStar 6 SE telescope, which was fitted 

with an illuminated Celestron Micro Guide eyepiece. 

A digital stopwatch that read out to the nearest 0.01 

seconds was used to find the scale constant of the linear 

scale in the eyepiece. All observations were made 

at Pine Mountain Observatory near Bend, Oregon on 

the nights of August 5 and 6, 2010 (B2010.594). 

Methods 

The participants polar aligned the telescope. The 

linear scale in the Micro Guide eyepiece was calibrated 

by observing the star Navi in the constellation 

Cassiopeia. Navi was selected for its reasonable 

brightness and favorable declination (60.717º). Stars 

with declinations above 70° move too slowly and stars 

below 45° move too quickly. The observers allowed 

Navi to drift down the linear scale by disabling the 

tracking motors. Ten drifts were timed with a stopwatch 

and the standard deviation and standard error 

of the mean were calculated. 

The scale constant was calculated by multiplying 

the average time (101.99 seconds) by the sidereal rate 

of the Earth's rotation (15.0411 arc seconds per second) 

and the cosine of the declination. This was then 

divided by the number of divisions on the linear scale 

(60). This equation yielded a scale constant of 12.50 

arc seconds per division. The standard deviation and 

standard error of the mean of these results were calculated 

to be 1.1 and 0.3 arc seconds per division, respectively. 

The angular separation between the primary and 

secondary stars was determined by carefully orienting 

the telescope so that one of the major divisions of the 

linear scale was between the two stars. The distance 

from the major division to each of the stars was estimated 

in minor divisions to one tenth of a minor division. 

Ten trials were performed (one of them was discarded 

as an outlier). The average, standard deviation, 

and standard error of the mean were calculated. 

The second parameter of double star measurement 

is the position angle, the angle that the primary 

and secondary stars make relative to celestial north. 

The observers chose to use the drift method as it is 

the most precise without adding an external protractor 

(Baxter 2010). This was carefully done by aligning 

the primary star, using the slow motion controls, with 

the central division of the linear scale while telescope 

tracking was active. Once the star was aligned with 

the center of the linear scale, the telescope's automatic 

tracking was disabled. The primary star then 

drifted across the inner protractor built into the eyepiece. 

The angle the star crossed was noted and recorded. 

An angle of 90° had to be added for the Celestron 

Micro Guide eyepiece correction (Teague 

2004). Position angle measurements were repeated 

five times for the first double star (61 Cyg) and ten 

times for the second (STF 123AB). Observations were 

limited by smoke from a nearby fire which obscured 

the stars. 

Observations 

The observers first selected a well known double 

star, 61 Cygni (STF 2758 AB), to learn the measurement 

methods. Table 1 gives the observational results. 

Table 1: Average, standard deviation, and standard 

error of the mean for the observed separation and position 

angle of 61 Cygni. 

Separation Position Angle 

Average 32.2” 151.4° 

Standard Deviation 2.1” 1.5° 

Mean Error 0.7” 0.4° 

The WDS Catalog's last entry for the separation 

of STF 2758 AB is 30.7”, while the observed average 

separation was 32.2”. Our percent error for the average 

separation was 4.9%, which is within one standard 

deviation. The authors attribute the large standard 

deviation and large difference from the catalog 

value to poor sky conditions due to nearby wildfire 

which increased scintillation. The WDS Catalog's entry 

for the position angle is 152.0°, while the observed 

position angle was 151.4°. The percent error for the 

position angle was 1.39% which is also within one 

standard deviation. These results can be considered 

accurate according to Ron Tanguay, an experienced 

double star observer, who stated that a difference of 

5% between observed and catalog values is adequate 

(Tanguay 1998, 2003). 

Based on the results from the first star, the observers 

felt confident enough to measure a less studied 

double star. Johnson selected the double star 

STTA 123 AB (RA: 13h 27m 04s Dec: +64° 44m 07s) 

because it fit the criteria of being bright enough 

(magnitude 7 or less) to be easily seen through a 

small telescope and had similar proper motion vec-

Vol. 8 No. 2 April 1, 2012 


Page 124 


tors, suggesting the pair may be a binary. Table 2 

presents the observational results. 

Table 2: Average, standard deviation, and standard error 

of the mean for the observed separation and position angle 

of 61 STTA 123 AB. 

The WDS Catalog's entry for the separation of 

STTA 123 AB was 68.9”, while the observed average 

separation was 69.9”. Our percent error for the average 

separation is 1.5% and within one standard deviation. 

The WDS Catalog's entry for the position angle 

is 147.0°, while the observed position angle was 

148.0°. The percent error for the position angle is 

0.7% and also within one standard deviation. We attribute 

the greater accuracy to the observers being 

more experienced and clearer sky conditions. 

Analysis 

Separation 

Position Angle 

Average 69.9” 148.0° 

Standard Deviation 1.8” 1.4° 

Mean Error 0.6” 0.4° 

Our primary goal for this project was to determine 

if a less studied double star (STTA 123 AB) is 

optical or binary in nature. We analyzed three of the 

properties of the two stars to determine if they were 

gravitationally bound: spectral type, stellar parallax, 

and proper motion vectors. To find these properties, 

the participants found both stars' HD designations in 

the SIMBAD database. The primary star's designation 

is HD 117200 and the secondary star's designation 

is HD 117201. 

If the spectral types of the two stars in a binary 

system are significantly different, the more luminous 

star should have a lower apparent magnitude. However, 

if the spectral type is the same, the apparent 

magnitude should be similar. The spectral type of the 

primary star is F0 and its magnitude is 6.6. The spectral 

type of the secondary star is also F0 and its magnitude 

is 7.0. Since the stars have the same spectral 

type and the difference in magnitude is only 0.4, the 

stars are probably a similar distance away from 

Earth. 

To quantify this observation, the students used 

stellar parallaxes to calculate the distance to each 

star in light years. The distance to a star in parsecs is 

equal to the reciprocal of the parallax in arc seconds. 

The distance in parsecs is multiplied by 3.26156 (the 

number of light years in a parsec) to find the distance 

in light years. The parallax for the primary star is 

0.01483” ± 0.00055”. This corresponds to a distance of 

220 light years. The parallax of the secondary star is 

0.01530” ± 0.00059”. This corresponds to a distance of 

213 light years. The minimum distance to the primary 

star is 212 light years and the maximum distance 

to the secondary star is 222 light years. Therefore, 

the difference between these two distances is 

well within the parallax errors. 

It is most likely that a double star is binary if the 

proper motion vectors of the two stars are within 10% 

of each other (Arnold 2010). Table 3 shows the proper 

motion vectors for the primary and secondary stars. 

The difference between the proper motion vectors of 

the primary and secondary is 2.9%. 

Table 3: Proper Motion Vectors for STTA 123 AB. 

Preliminary Orbit Calculation 

Because the separation and position angle have 

not changed significantly since the first observation 

in 1876, a circular orbit could be assumed. The 

masses of the two stars in solar masses (M1 and M2), 

their separation in astronomical units (A), and their 

period in years (P) can be calculated using Newton's 

modification of Kepler's third law: 

M1 + M2 = A 3 /P 2 

1.4 +1.4 = 316 3 / P 2 

Right Ascension 

(mas/yr) 

Declination 

(mas/yr) 

Primary Star -68.76 35.16 

Secondary Star -69.74 34.62 

Since both stars have the spectral type F0, their 

masses can be estimated to be 1.4 M based on the 

Hertzsprung-Russell diagram. This can only be done 

if the stars are on the main sequence where there is a 

strong correlation of luminosity and mass. If both 

stars are assumed to be the same distance from 

Earth, the distance between the two stars can be calculated 

by dividing the cosine of the separation in degrees 

(0.00319°) by the mean distance to the stars 

(216.5 light years). This equates to a separation of 

about 0.005 light years (316 AU). The equation yields 

a period of about 3357 years. This long orbit is ex-

Vol. 8 No. 2 April 1, 2012 


Page 125 


pected as the separation and position angle appear to 

have changed little since the double star was first observed 

in 1876. The first reported separation was 

68.9” and the first reported position angle was 147°, 

both within the standard deviation of the present 

study. 

However, the similarity between the first observations 

and present observations are slightly suspect. 

Even with such a large orbit, a shift of at least 14° 

should have been seen in the last 134 years if the orbital 

plane is oriented at 90° to our line of sight. If the 

1° shift in position angle is real, the orbit should be on 

the order of 48,000 years which is inconsistent with 

the calculated distance between them. Thus, the authors 

offer four suggestions to account for the discrepancy 

between the observed and calculated position 

angles: 1) The secondary star has actually been 

ejected from the system and is now moving linearly 

away from the primary such that there should be no 

significant shift in position angle; 2) The orbital plane 

has a minimal inclination to our line of sight and the 

secondary star is moving either toward Earth or away 

from Earth relative to the primary; 3) The orbit is not 

circular and the secondary is near greatest elongation 

from the primary; or 4) The orbit is both inclined and 

eccentric. 

According to double star observer Paul Couteau 

(1981), an eccentricity correction factor of 1.25 can be 

applied to most binary star systems to account for 

elongated orbits. For STTA 123 AB, this would equate 

to a semi-major axis of 395 AU and a period of 4691 

years. However, a change in position angle of at least 

10° would still be expected over 134 years. Thus, the 

authors believe the orbit is also inclined to our line of 

sight, decreasing the expected change in position angle. 

Future researchers may determine the true eccentricity 

and inclination of the orbit. 

Conclusions 

The participants analyzed a double star to determine 

if it is likely to be an optical or binary pair. Because 

the stars have similar apparent magnitudes 

and spectral types, they are probably a similar distance 

from Earth. To confirm that this is likely, the 

participants calculated the distances to the stars using 

stellar parallaxes obtained from the SIMBAD database. 

The difference in the calculated distances 

were within the error of the stellar parallaxes. Furthermore, 

the proper motion vectors of the two stars 

are similar enough to suggest they are moving 

through space together. Thus, the participants conclude 

that the double star STTA 123 AB is likely a 

binary system. 

Johnson then calculated a preliminary circular 

orbit and determined the masses of the two stars 

along with their separation in astronomical units and 

period in years. Currently, STTA 123 AB only has 23 

reported observations in the WDS Catalog. Because 

the system is likely binary, it is deserving of further 

study to resolve its orbit. 

Arnold then studied the calculated orbit and predicted 

what the observations should be. A discrepancy 

was found in that the position angle should have 

shifted by at least 14°, yet it has not significantly 

changed. The authors suggest that the orbit is eccentric 

and inclined to our line of sight such that the position 

angle has not significantly changed. This would 

make the orbit a level 5 according to the Sky Catalog 

2000 description where this is a rough or preliminary 

orbit that may be useful to future researchers. Alternatively, 

there is a chance that the stars are very 

close together in space but are not in a binary system 

and future observers will see linear motion. 

Over the course of the three day workshop, the 

students took quantitative measurements of two double 

stars, one well known and one much less known. 

The students also calculated the average, standard 

deviation, and standard error of the mean, and included 

their observations in a scientific paper. 

Through this process, the observers learned a technique 

for measuring double stars with an astrometric 

eyepiece. What they learned can be taken back to Evergreen 

State College and taught to other students. 

Acknowledgments 

The authors would like to thank the University of 

Oregon's Pine Mountain Observatory for the use of 

their facilities and Richard Berry for directing the 

workshop. The authors would also like to thank the 

Evergreen State College for offering the program 

which allowed the students this opportunity. The authors 

thank Russ Genet for the use of his NexStar 6 

SE. Finally, the authors thank Tom Frey, Chris 

Estrada, Russ Genet, and Vera Wallen for their kind 

reviews of this paper. 

References 

Arnold, Dave. “Considering Proper Motion in the 

Analysis of Visual Double Star Observations.” In 

Small Telescopes and Astronomical Research. 

(2010). Eds. Russ Genet, Jolyon Johnson, and

Vol. 8 No. 2 April 1, 2012 


Page 126 


Vera Wallen. Santa Margarita, CA: Collins Foundation 

Press. 

Baxter, Alexandra, Jolyon Johnson, Russell Genet, 

Chris Estrada, and Danyal Medley. “Comparison 

of Two Methods of Determining the Position Angle 

of the Visual Double Star 61 Cygni with a Celestron 

Micro Guide Eyepiece.” Journal of Double 

Star Observations. Submitted. 

Couteau, Paul. Observing Visual Double Stars. (1981). 

Massachusetts Institute of Technology. 

Johnson, Jolyon. “Double Star Research as a Form of 

Education for Community College and High 

School Students.” In Proceedings for the 27 th Annual 

Conference for the Society for Astronomical 

Sciences. (2008). Eds. Brian Warner, Jerry Foote, 

David Kenyon, and Dale Mais. 

Mason, Brian. The Washington Double Star Catalog. 

October 2008. Astrometry Department, U.S. 

Naval Observatory. http://ad.usno.navy.mil/wds/ 

wds.html. 

Tanguay, Ronald. The Double Star Observer’s Handbook, 

Editions 1 & 2. Saugus, MA: Double Star 

Observer, 1998 & 2003. 

SIMBAD Astronomical Database. Centre de Données 

Astronomiques de Strasbourg. August 6, 2010. 

http://simbad.u-strasbg.fr/simbad/. 

Teague, Tom. “Simple Techniques of Measurement.” 

In Observing and Measuring Visual Double Stars. 

(2004). Ed. Bob Argyle. London: Springer. 

Nick Brashear (major undeclared), Angel Camama (cognitive science and new media), 

Miles Drake (astronomy and writing), and Miranda Smith (international studies) are undergraduate 

students at Evergreen State College in Olympia, Washington. Jolyon Johnson 

is a geology student at California State University, Chico, and led the research team. Dave 

Arnold is an amateur astronomer and highly experienced double star observer in Flagstaff, 

Arizona. Rebecca Chamberlain is a professor of science and humanities at Evergreen State 

College.

Vol. 8 No. 2 April 1, 2012 


Page 127 

Orbital Elements for BU 741 AB, STF 333 AB, 

BU 920 and R 207 

Francisco Rica 

C/José Ruíz Azorín, 14, 4º D, 06800, 

Mérida, Spain 

Abstract: New orbital parameters and dynamical masses for WDS 02572-2458 (BU 741 

AB), WDS 02592+2120 (STF 333 AB), WDS 12158-2321 (BU 920) and WDS 12463-6806 (R 

207) were determined due to large residuals. The Thiele-van den Bos method was used to 

obtain initial orbits for all the binaries (except for STF 333 AB where the Docobo method 

was used). The initial orbital solutions were improved using the differential correction 

method of Heintz. The physical relation of wide components was studied using BVIJHK 

photometry, historical astrometry and kinematical data. A search for new unreported companions 

around the binaries was performed as well. 

Introduction 

As a result of part of the work on visual double 

stars carried our by the Double Star Section of Liga 

Iberoamericana de Astronomía (LIADA), I present 

orbital parameters and other data (residuals, 

ephemerides, masses, parallaxes, apparent orbits, 

etc.) for four visual binary systems: WDS 02572-2458 

(BU 741 AB), WDS 02592+2120 (STF 333 AB), WDS 

12158-2321 (BU 920) and WDS 12463-6806 (R 207). 

For all binaries, except STF 333 AB, initial orbits 

were calculated using the method of Thiele-van den 

Bos which were improved using the differential correction 

method of Heintz (1978a). For STF 333 AB, 

the analytical method of Docobo (1985) was used. 

Dynamical parallaxes were calculated using the 

Baize-Romaní algorithm (1946). 

The physical relation for wide components was 

studied using BVIJHK photometry, historical astrometry 

and kinematical data. The nature for these 

wide components was determined by the use of several 

criteria. 

Astrophysical properties for binaries were determined 

and discussed. All the orbits presented here 

have previously been announced in the Information 

Circular of IAU Commission 26 (hereafter IAUDS). 

Method of Orbital Calculation 

Before using any analytical method, θ was corrected 

for precession and proper motion. Theta and ρ 

were plotted against time which allows the detection 

of measures with important errors and quadrant 

problems. The measures with very large errors are 

assigned zero weight. 

Preliminary orbits were determined by the 

method of Thiele van den Bos. Three base points and 

a crude value of areal constant c are needed. I obtained 

a set of Keplerian orbits changing the initial 

value of the areal constant over a range of ±50 percent 

of the initial value of c. The apparent orbits for 

the set of orbits pass through the three given points. 

Only periodic orbits are taken into account. The step 

size and the search range for c are customizable. 

The orbit with minimum RMS residuals is retained. 

In the next iteration the search range and the 

step size are reduced and the areal constant is centered 

in the c value for the orbit retained. The process 

is repeated until the result for two iterations

Vol. 8 No. 2 April 1, 2012 


Page 128 

Orbital Elements for BU 741 AB, STF 333 AB, BU 920 and R 207 

doesn’t show a significant difference. Two or three 

iterations are sufficient for most of the binaries. 

The orbital elements of STF 333 were calculated 

using Docobo's analytical method (Docobo 1985). It is 

briefly summarized in Docobo et al. (2000) and 

Tamazian et al. (2002). This method is applicable 

even when only a relatively short and linear arc of the 

orbit has been measured. The advantage of this 

method, over other formal solutions, is that it does 

not require knowledge of the areal constant. A family 

of Keplerian orbits is generated whose apparent orbits 

pass through three base points. Simultaneously, 

O-C (observed minus calculated) residuals in both ρ 

and θ are determined for these orbits. 

The next step is to select the orbit with smallest 

weighted rms values for ρ and θ. Usually, the orbit 

with the smallest rms values in θ is not exactly the 

same as the orbit with the smallest rms values in ρ. 

In this case, I selected the orbit with minimum residuals 

calculated by the followed formula: 

n 

n 

2 2 2 

= wθi( i Δ i) 

+ wρiΔ 

i 

i= 1 i= 

1 

∑ ∑ (1) 

χ ρ θ ρ 

where w θ i and w ρ i are the weights for the i th θ 

and ρ measure. Δθ (expressed in radians) and Δρ are 

the O-C residuals for θ and ρ. 

If the set of Keplerian orbits shows a flat gradient 

for RMS, then some orbits are rejected by the comparison 

of the dynamic mass with those determined 

using spectral types. 

The three base points have to be chosen carefully 

where the observational data seems most reliable 

with respect to instrumentation, data density, or critical 

arc coverage. I also tried to cover as much of the 

observed arc as possible. This may let the area 

around a single observation represent a base point 

without additional observational coverage. 

Initial orbits were improved using the Heintz differential 

correction method (1978a). 

The initial weights were assigned using a data 

weighting scheme based on Hartkopf et al. (1989), 

Mason et al. (1999a), Seymour et al. (2002), and Docobo 

& Ling (2003). The initial θ weights were 5 times 

larger than ρ weights. 

After several iterations in the differential correction 

process the measures with residuals larger than 

3σ were assigned zero weight. Later the non-zero 

weight measures were reassigned following the work 

of Irwin et al. (1996). 

Results 

Table 1 lists, for each binary, the date of its discovery, 

the final orbital elements, the root mean 

squared (RMS) residuals and mean absolute residuals 

(MA) residuals. These are in both cases weighted averages 

calculated using the data-weighting scheme 

described in earlier. 

The a 3 /P 2 values are also listed. Errors for the 

elements were calculated from the covariance matrix 

and the residuals to all observations. 

Table 2 presents ephemerides for the period 2012- 

2021. Table 3 lists the stellar data for the system 

studied. The WDS magnitudes in columns (3) and (4) 

and WDS spectral types in column (5); in column (6), 

the dynamical parallaxes calculated therefrom using 

the orbital periods and semimajor axes obtained in 

this work; in columns (7) and (8) the apparent magnitudes 

published in the Hipparcos and Tycho catalogs 

(ESA 1997) and in column (9) the corresponding trigonometric 

parallaxes (with their standard errors) from 

the re-reduced Hipparcos parallax (Leeuwen 2007); in 

column (10) the total mass of the binary (± estimated 

standard error), as calculated from the Hipparcos parallax. 

Figures 1-4 show the new apparent orbits drawn 

together with the observational data; the x and y 

scales are in arcseconds. The solid curve represents 

the newly determined orbit, while the dashed curve 

represents the previous orbit. The line passing 

through the origin indicates the line of nodes. Speckle 

measures are shown as filled squares, visual interferometric 

observations are showed as open circles, visual 

measures as plus signs, and measures from the 

ESA Hipparcos instrument are indicated as a red 

empty square. The rejected observations are shown as 

red points. All measures are connected to their predicted 

positions on the new orbit by O - C lines. 

Notes for Same Systems 

In the next section, photometric, astrometric, 

spectroscopy and kinematical data are analyzed. 

Spectral types and luminosity classes, masses and 

dynamical parallaxes are obtained. The dynamical 

parallax was calculated using the Baize-Romani 

method (Baize & Romaní 1946). 

A kinematical study was performed to determine 

the stellar age. From galactocentric velocity (U, V, W), 

I use the Eggen (1969a, 1969b) and Chiba & Beers 

(2000) diagrams the kinematic age parameter of 


Vol. 8 No. 2 April 1, 2012 


Page 129 


Name 

WDS 

ADS 

HIP 

BU 741 AB 

02572-2458 

2242 

18455 

STF 333 AB 

02592+2120 

2257 

13914 

R 207 

12463-6806 

62322 

BU 920 

12158-2321 

8481 

59801 

Disc. date 1879.70 1827.16 1880.34 1879.57 

P [years] 149.89±4.48 1215.913±1.540 194.276±2.65 873.041±25.251 

T [years] 1870.68±4.22 704.111±1.778 1857.504±3.79 1764.260±6.576 

e 0.602±0.016 0.317±0.006 0.598±0.057 0.166±0.026 

a ["] 1.425±0.077 2.174±0.035 0.969±0.068 2.012±0.137 

i [º] 83.0±0.2 84.2±0.8 37.1±6.5 63.5±3.9 

ω [ º ] 260.8±1.6 162.1±1.0 209.0±4.1 28.0±3.6 

Ω [ º ] 163.5±0.5 25.6±0.7 349.4±4.2 142.2±3.7 

Residuals: 

Table 1: Orbital parameters, parallaxes, and residuals. 

RMS(θ)[ º ] 1.06 0.99 1.62 2.19 

RMS(ρ)[ “] 0.021 0.042 0.13 0.058 

MA(θ)[ º ] 0.64 0.63 1.14 1.46 

MA(ρ)[ " ] 0.009 0.021 0.077 0.034 

a 3 /P 2 [arcsec 3 *yr -2 ] 9.03813*10 -5 3.196790*10 -6 2.48776*10 -5 5.311127*10 -6 

Epoch 

θ 

(deg) 

02572-2458 02592+2120 12463-6806 12158-2321 

ρ 

(arcsec) 

Table 2: Ephemerides 

θ 

(deg) 

ρ 

(arcsec) 

θ 

(deg) 

ρ 

(arcsec) 

θ 

(deg) 

ρ 

(arcsec) 

2012 343.6 0.818 209.5 1.358 54.9 0.934 306.5 1.872 

2013 344.4 0.767 209.6 1.353 56.2 0.918 306.7 1.879 

2014 345.3 0.709 209.7 1.347 57.5 0.903 306.9 1.886 

2015 346.3 0.642 209.7 1.342 58.9 0.887 307.1 1.894 

2016 347.6 0.565 209.8 1.336 60.4 0.870 307.3 1.901 

2017 349.4 0.478 209.9 1.331 61.9 0.854 307.5 1.908 

2018 352.0 0.382 209.9 1.331 63.4 0.838 307.7 1.915 

2019 356.4 0.278 209.9 1.331 65.0 0.821 307.9 1.922 

2020 6.4 0.171 209.9 1.331 66.7 0.805 308.1 1.929 

2021 43.8 0.080 209.9 1.331 68.5 0.788 308.3 1.936

Vol. 8 No. 2 April 1, 2012 


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WDS 

(1) 

STAR 

HIP 

(2) 

m A 

(3) 

m B 

(4) 

WDS 

Spectral 

Type 

(5) 

Table 3: Stellar data 

PRESENT WORK 

π (Dynamical) 

(mas) 

(6) 

HpA 

(7) 

HpB 

(8) 

Hipparcos 

π 

(Trigonometric) 

(mas) 

(9) 

02572-2458 18455 8.06 8.20 K1/2V 45.0 8.19 8.26 44.51 ± 2.09 1.5 ± 0.3 

02592+2120 13914 5.17 5.57 A2Vs A2Vs … 5.24 5.59 9.81 ± 0.79 7.4 ± 1.8 

12463-6806 62322 3.52 3.98 B2.5V 11.3 3.51 4.01 10.48 ± 0.65 20.9 ± 5.9 

12158-2321 59801 6.86 8.22 F7V 15.6 6.91 8.29 14.37 ± 0.71 3.60 ± 0.93 

Σ 

(M 

) 

(10) 

Grenon (1987), fG. Bartkevicius & Gudas (2002) determined 

the relation between fG and the age. Statistically, 

the stars with fG < 0.20 belong to the youngmiddle 

age group (with an age less than 3 - 4 Gyr) of 

the thin disk population. The stars with 0.20 < fG < 

0.35 belong to the old (with age of 3 - 10 Gyrs) thin 

disk population. The stars with 0.35 < fG < 0.70 belong 

to the thick disk population (age greater than 10 

Gyrs) and the stars with fG > 0.70 belong to the halo 

population. 

In order to check the membership of the binaries 

to young kinematic groups, I consulted Table 1 published 

in Montes et al. (2001) and Soderblom & Mayor 

(1993). 

WDS 02572-2458 = BU 741 AB 

Since the first measure in 1879 (Burnham 1887) 

this binary has had 69 measures which cover an arc 

of about 184 deg. The orbital elements have previously 

been announced in the Information IAUDS No. 

172 (Rica 2010). 

BU 741 AB (HD18455 = HIP13772) is composed 

by stars of 8.06 and 8.20 magnitudes (ESA 1997) in 

Hipparcos system and the previous orbit was calculated 

by Scardia (2002). 

Tycho-2 catalog lists a proper motion of +31.5 ± 

2.6 mas/yr in RA and –35.1 ± 2.4 mas/yr in dec. The rereduced 

Hipparcos trigonometric parallax is 44.51 ± 

2.09 mas which corresponds to a distance of 25 +/- 

Figure 1: Apparent orbit for BU 741.

Vol. 8 No. 2 April 1, 2012 


Page 131 


1.1/1.0 pc. 

Masses were calculated taking into account the 

standard deviation for Hipparcos trigonometric parallax, 

P and a. A total dynamic mass of 1.46 ± 0.33 M 

was obtained. From spectral types, stellar masses of 

0.73 and 0.73 M were calculated using Allen’s tables 

(1973) and so the sum of the masses is in excellent 

agreement with that calculated using orbital parameters. 

The dynamic parallax is 45.0 mas in good agree 

with Hipparcos data. 

In the astronomical literature BU 741 AB has 

been classified as a K1/2V star (Houk 1988) while 

Gray (2006) classified it as a K2V star. From differential 

magnitude and combined spectral type, I determined 

individual spectral type of about K2V and K2V 

(tables from Cowley et al. (1969), Christy & Walker 

(1969) and Edwards (1976) were used). From V apparent 

magnitudes and Hipparcos parallax the absolute 

magnitudes are +6.30 and +6.44 which corresponds 

to a spectral type of K1/2V and K2V. 

Favata, Micela & Sciortino (1997) measured a 

metallicity [Fe/H] = -0.47 ± 0.05 for GJ 120.1A 

(matching with BU 741 AB). While Taylor (2005) 

measured a metallicity of -0.216 ± 0.087, Gray (2006) 

gave a value of -0.15 ± 0.06 and Holmberg, Nordstrom 

& Andersen (2009), -0.10. 

Bobylev, Goncharov, & Bajkova (2006) measured 

a radial velocity for AB of +50.4 ± 0.2 Km s -1 while 

Gontcharov (2006) measured a radial velocity of +50.7 

± 0.3 km s -1 . In 2012 the calculated relative radial 

velocity will be of -9.1 km s -1 when the secondary is at 

0.815 arcsec of angular distance. Perhaps this would 

be a good time for this system to be observed spectroscopically. 

Age and Stellar Population. 

Bobylev, Goncharov, & Bajkova calculated a galactocentric 

velocity of (U,V,W) = (-18.5, -18.8, -43.3) 

km/s. According to this kinematic data this system is 

a member of the young galactic disk in agree with the 

study of Bartkevicius & Gudas (2002). A fG = 0.29 

was obtained in this work corresponding to old age 

thin disk stars of 3-10 Gyr old. 

The ROSAT All-Sky Survey Faint Source Catalog 

(Voges et. al. 2000) lists the X-ray source 1RXS 

J025714.6-245828 located at 20 arcsec from AB and 

about 19 arcsec from component C. The positional 

error for this source is of 20 arcsec and the count rate 

is of 0.0291 ± 0.0125 cts/s with a HR1 = -1.00 ± 0.68. 

The optical source that emits in X-ray is unknown. 

How can I identify the possible X-ray optical counterpart 

Agüeros et al. (2009) calculated that most of 

the optical counterpart is at less than twice the 

ROSAT positional error. So I search for an optical 

source in a radius of 40 arcsec from the X-ray source. 

There are no galaxies near the X-ray source so only 

two candidates were found: BU 741 AB and S 423 C. 

Both candidates have a log fx/fv that match with K 

dwarf stars. 

Using ROSAT data and the Hipparcos parallax I 

calculated a log Lx = 29.7 +/- 0.5/2.1 ergs/s for the AB 

pair. If I consider that A and B stars contribute 

equally to the X-ray emission then the Lx for each 

component would be of about 29.4. This very high 

level of X-ray emission is a strong indicator of stellar 

youth and it is a level typical for very young stars. 

Using he graphics cited in Catalán et al. (2008) and 

Daminani et al. (1995), the age for AB could be of 

about 200 Myr but the large errors in the count rate 

and in HR1 gave high limits of about 6 Gyr. 

WDS 02592+2120 = STF 333 AB 

This stellar system is located behind the dark 

cloud MBM12 (Abt & Morrell (1995)). Since Struve 

(1837) discovered it in 1827, STF 333 AB (= ADS 2257 

AB = HD 18520/HD18519 = ε Ari = 48 Ari) has had 

439 measures which cover about 19 degrees in a large 

nearly rectilinear arc. In the x(t) and y(t) plots can be 

observed a slightly curve cloud of points, clear evidence 

that STF 333 AB is a binary star. 

The first speckle measure was performed in 

1978 (McAlister & Fekel 1980). Since then, 45 speckle 

measures have been made. This binary is wide 

enough for amateurs to measure. For example 

Comellas (2003) measured it in 1973 and 1980, Le 

Beau (1987) in 1985, Kaznika (1994) in 1991, Tofol 

Tobal (2003) between 1984 and 1990, Benavides 

Palencia (2003) in 2002; Alzner (1998, 2003, 2005) 

between 1997 and 2004, Roberto Caloi (2008) in 2007, 

James Daley (2003) in 2001. 

This orbit has previously been announced in the 

Information IAUDS No. 169 (Rica 2009). 

STF 333 AB has stars of 5.17 and 5.57 magnitudes 

(ESA 1997) with combined spectral type of 

A2Vs. Tycho-2 catalog (Hog et al. 2000) determined a 

proper motion of –9.4 mas yr -1 in AR and –5.0 mas yr -1 

in DEC. The Hipparcos trigonometric parallax of 9.81 

± 0.79 mas (Leeuwen 2007) corresponds to a distance 

of 101.9 +/- 8.9/7.6 

Masses were calculated taking into account the 

standard deviation for Hipparcos trigonometric parallax 

and the errors of P and a. A total mass of 7.35 ± 

1.81 M was obtained. 

Gray & Garrison (1987) obtained a spectral type

Vol. 8 No. 2 April 1, 2012 


Page 132 


Figure 2: Apparent orbit for STF 333 AB. 

of A2IV for primary and secondary, while Abt & 

Morrell (1995) obtained A2IV and A3IV. Others references 

classify the components as dwarf stars. From 

apparent magnitudes and Hipparcos parallaxes, the 

absolute magnitudes for the components were determined 

to be +0.13 ± 0.18 and +0.53 ± 0.18. It is a suspected 

variable star cataloged as NSV 1001. 

The result of differential photometry from the 

Hipparcos satellite is +0.40. The mean result using 

the historical values from the WDS catalog was +0.38 

± 0.55. 

Using theoretical isochrones, I calculated a stellar 

mass of 2.4 for an A2 subgiant, therefore, the sum of 

the masses is 4.8 M. 

Age and Stellar Population 

In this work, theoretical isochrones were used to 

determine that both stars seems to be subgiant stars 

with an age of about 550 - 650 Myr. King et al. (2003) 

obtained a galactic heliocentric velocity of (U, V, W) = 

(+9.9,+4.1,-1.0) km/s and considered that both component 

could be members of the Ursa Major moving 

group based in photometric data. The age for the Ursa 

Major moving group calculated by King et al. (2003) 

was 500 ± 100 Myr in excellent agreement with the 

age calculated in this work. According to Eggen’s diagrams, 

STF 333 AB is a member of the young Galactic 

disk. 

Coster (2009) published other orbital parameters 

with a very shorter orbital period (313 years). The 

ephemerids for both orbits are very similar and new 

measures in the followed years could not determine 

which orbit was correct. 

WDS 12463-6806 = R 207 

Since Russell (1871) discovered it in 1871, R 207 

(= β Muscae = HD 110879 = HIP 62322) has had 78 

measures which cover about 2/3 of the period. Only 

three speckle measures were made (Hartkopf et al. 

1993; Davis & North 2001; Horch et. al. 2006). The 

last two measures were performed by the German 

amateur Rainer Anton (2006, 2008) in 2002.686 and 

2007.373 using telescopes of 0.20 and 0.28 meters by 

CCD lucky imaging technique. 

The official orbit was calculated by Mourao (1964) 

and it is an orbit of grade 5. Since the previous orbit, 

20 measures have been made covering about 28 degrees. 

R 207 is composed of stars of 3.54 and 3.99 magnitudes 

(Hog et al. 2000) with combined spectral type of 

B2V (Houk & Cowley 1975; Kennedy 1983; Burnashev 

1985; Buscombe & Foster 1995).

Vol. 8 No. 2 April 1, 2012 


Page 133 


Figure 3: Apparent orbit for R 207. 

Corbally (1984) obtained the followed photometric 

data: V = 3.58, B-V = -0.20, U-B = -0.77, and Mv = - 

2.50 for the primary. For the secondary V = 4.10, B-V 

= -0.18, U-B = -0.69, and Mv = -2.00. Tycho-2 catalog 

listed photometric data which transformed to standard 

system are: V = 3.54 ± 0.01, B-V = -0.16 ± 0.01 

for the primary and V = 3.99 ± 0.01, B-V = -0.15 ± 

0.01 for the secondary. 

Corbally also estimated spectral types B2V and 

B2.5V for the components and a reddening E(B-V) of 

0.04. Sartori, Lepine & Dias (2003) estimated a color 

V-I = -0.19 and Av = 0.05 and a bolometric correction 

of -2.05. 

Hipparcos catalog (ESA 1997) determined a 

proper motion of –40.40 mas yr -1 in AR and –10.32 

mas yr -1 in DEC and a trigonometric parallax of 10.48 

± 0.65 mas which corresponds to a distance of 95 +/- 

6.3/-5.6. 

Stellar masses were calculated taking into account 

the standard deviation for Hipparcos trigonometric 

parallax. A total mass of 20.9 ± 5.9 M was 

obtained. 

From Tycho-2 apparent magnitudes and Hipparcos 

parallaxes the absolute magnitudes were calculated 

for the components (-1.48 ± 0.13 and -1.03 ± 

0.13). 

From spectral types obtained by Corbally 

(1984), stellar masses of 11.6 and 10.4 M¤ were calculated 

using Allen’s tables (1973). The sum of the 

masses is 22.0 M¤ and the dynamic parallax is 11.3 

mas in agreement with what I expected. 

Age and Stellar Population 

Sartori, Lepine & Dias (2003) obtained a galactic 

heliocentric velocity with respect to the LSR of (U, V, 

W) = (+16.9, -39.4, -1.6) km s -1 and a radial velocity of 

+42.0 km/s. 

According to this kinematic data, R 207 is a member 

of the old Galactic disk. A value of 0.22 for fG was 

obtained in this work corresponding to old age thin 

disk stars. This is not in agreement with the age inferred 

by their spectral types. I estimate the most 

probable age using the stellar models by Girardi et al. 

(2002; using the web interface PARAM 1.1, Da Silva 

et al. 2006). It yields stellar ages of about 100 Myrs 

(assuming solar metallicity). I know no reason for this 

different conclusion using kinematic data but is obviously 

more logical think that two dwarfs of B spectral 

type are very young objects.

Vol. 8 No. 2 April 1, 2012 


Page 134 


WDS 12158-2321 = BU 920 

The first measure was performed in 1879 

(Burnham 1883) In this work, a combined spectral 

type of F5V (using BVIJHK photometry) was obtained. 

From apparent magnitudes and Hipparcos 

parallax the absolute magnitude for the components 

are +2.65 ± 0.11 and +4.01 ± 0.11. This binary has 

had 62 measures which cover an arc of 70 degrees. 

BU 920 is composed of stars of 6.86 and 8.22 magnitudes 

(ESA 1997). Tycho-2 catalog lists a proper motion 

of -8.7 ± 3.4 mas yr -1 in RA and -38.5 ± 3.3 mas yr 

-1 in DEC and a trigonometric parallax of 14.37 ± 0.71 

mas which corresponds to a distance of 69.6 +/- +3.6/- 

3.3 pc. 

In the astronomical literature BU 920 has been 

classified as an F3V star (Malaroda 1975), F5/6V 

(Houk & Smith-Moore 1988), F7V 

The astronomical literature gives values for the 

radial velocity ranging from +18.1 ± 4.0 km/s 

(Gontcharov 2006) to +22.1 ± 1.5 km/s (Beavers & Eitter 

1986). 

If both stars are dwarfs, the individual spectral 

types determined in this work would be F3V and 

G1V. Using an evolutionary isochronal, the primary 

could be an evolved star of spectral type F3IV/V. The 

sum of the masses could be 3.6 M (2.3 solar masses 

for the primary). A total mass of 3.60 ± 0.93 M was 

obtained using the orbit of this work and the errors in 

trigonometric parallax, P and a. 

No common proper motion companion was found. 

Age and Stellar Population. 

Holmberg, Nordström & Andersen (2009) calculated 

a galactocentric velocity of (U, V, W) = (+8, -21, 

+1) km s -1 , a metallicity [Fe/H] = +0.01 and an age of 

1.8 +/- 0.2/0.1 Gyr. Philip & Egret (1980) calculated 

[Fe/H] = +0.16. According to the diagram of Chiba & 

Beers (2000) this system is a member of the thin galactic 

disk. A fG = 0.11 was obtained in this work corresponding 

to young-middle age thin disk stars of 3-4 

Gyr old. 

Study of Wide Companions 

The astronomical literature was consulted in order 

to obtain photometric, astrometric and kinematic 

data. VizieR, Simbad (Wenger et al. 2003) and the 

“services abstract” tools were used from the website of 

Centre De Données Astronomiques de Strasbourg. 

Photometry in B, V and I bands came from Hipparcos 

(ESA 1997) and Tycho-2 catalogs (Høg et al. 2000). 

Infrared J, H and K photometry came from Two Micron 

All Sky Catalogue (Cutri et al. 2000), hereafter 

2MASS. Proper motion came from Tycho-2 catalog. 

Figure 4: Apparent orbit of BU 920

Vol. 8 No. 2 April 1, 2012 


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This catalog was chosen because the Hipparcos 

proper motions could be affected by Keplerian motion 

due to its smaller time baseline. Historical astrometric 

data were supplied kindly by Mason. Spectral 

types and other astrophysical data were taken from 

other sources. 

The details about the process to estimate spectral 

types and luminosity classes for the members, the 

calculus of interstellar reddening, determination of 

the nature for the stellar systems, the expected semimajor 

axis and the orbital period were explained in 

detail in an earlier paper (Rica 2008). 

5.2 STF 333 C. 

The component C of STF 333 is a star of 12.7 

magnitudes (from WDS) at about 145.0 arcsec to the 

primary component. It was measured for the first 

time in 1912 by Burnham (1918) when the angular 

separation was 145.4 arcsec. But later, an earlier 

measure on 1896 was added from the WFC (Urban et 

al. 1998). Since then, it has been measured only 4 

times, the last in 1998 from 2MASS catalog. 

Using these four measures I calculated that the 

relative motion of C with respect to A was: Δx = -4.6 ± 

1.3 mas/yr and Δy = +3.5 ± 2.9 mas/yr. The time baseline 

of the 4 measures used was nearly 102 years. The 

proper motion of C was calculated using the proper 

motion of A and the relative motion of C: μ(α) = -14.0 

± 1.8 mas/yr and μ(δ) = +1.5 ± 4.1 mas/yr. The UCAC-2 

catalog lists a proper motion of μ(α) = -14.0 ± 1.9 mas/yr 

and μ(δ) = 0.0 ± 1.9 mas/yr in good agreement with 

our result. 

Using the magnitude r from CMC14 and JHK 

from 2MASS, I determined the V magnitude for C 

using the relation of John Greaves (private communication; 

see Rica 2011). The result was V = 12.51 ± 

0.06. In order to obtain another independent result 

for V magnitude, I obtained calibrated photometric 

data from GSC 1.2 catalog, using Tycho-2 stars for 

the region of the sky where the component C is located. 

A magnitude V = 12.48 ± 0.40 was calculated. 

No spectral type information was found in the 

literature. Using V magnitude, JHK photometric data 

from 2MASS, and proper motion, a spectral type of 

K0V was determined. But this stellar system is behind 

the dark nebula MBM12 and could be very reddened. 

A value of E(B-V) = +0.32 was calculated. This 

suggests that the C component is an F8V star at a 

distance of about 322 pc. 

In order to determine the nature of the wide C 

component, several tests were used: Dommanget test 

(1955, 1956), van de Kamp test (1961), Sinachopoulos 

& Mouzourakis test (1992). Consult Benavides et al. 

(2010) for detailed information about these criteria. 

The component C is not bound gravitationally to the 

A component. 

5.3. S 423 AB-C. 

The C component (HD 18445 = HIP 13769) of the 

WDS 02572-2458 stellar system is a star of magnitude 

7.84 (ESA 1997) at about 29 arcsecs to BU 741 

AB. It was measured for the first time in 1824 by 

South (1826) when the angular separation was of 

27.75 arcsecs from the AB close pair. Since then, it 

has been measured 32 times, the last in 2008 by Anton 

(2010) when the angular separation was of 28.93 

arcsecs. 

According to the data from the Hipparcos satellite, 

the trigonometric parallax is 38.35 ± 1.24 

(distance of 26.1 +/- 0.9/-0.8 pc with magnitudes and 

colors V = +7.83; B-V = +0.960 ± 0.006 and V-I = +0.95 

± 0.01. 

Beuzit et al. (2004) discovered in 2000 that C is a 

binary star (the binary star was called BEU 4 Ca, 

Cb). At that moment, Cb component was at 0.083 

arcsecs to Ca in direction 170.1 deg. Beuzit et al. observed 

a difference of 0.02 magnitudes in K band and 

Tokovinin, Mason, & Hartkopf (2010) determined a 

difference of 0.4 magnitudes in R band. Since its discovery, 

BEU 4 Ca, Cb has been measures three times. 

I calculated the relative motion of C with respect 

to AB: Δx = -16.8 ± 0.6 mas/yr and Δy = +3.1 ± 0.6 mas/yr. 

The time baseline of the 32 measures used was nearly 

184 years. The proper motion of C is listed in Tycho-2 

catalog: μ(α) = +15.0 ± 1.2 mas/yr and μ(δ) = -32.6 ± 

1.3 mas/yr in good agreement with our results. 

In the literature, the C component is listed as a 

K2V star (Houk (1988) and Montes et al. (2001)) and 

as a K3V star of [Fe/H] = -0.09 ± 0.06 (Gray et al. 

2006). In this work, I used the BVI photometry from 

Hipparcos and JHK photometry from 2MASS to obtain 

a K3V spectral type. 

In order to determine the nature of the wide C 

component, I estimate that AB and C are at the same 

distance at a 2σ level (Hipparcos lists a trigonometric 

parallax of 44.51 ± 2.09 for AB and 38.35 ± 1.24 for C 

(Leuwann 2007)). The proper motions for AB and C 

are mathematically incompatible, but taking into account 

that they are nearby stars, the relative motion 

could be caused by the orbital motion. The radial velocity 

for the components is an excellent test. In the 

literature the radial velocity for C ranges from +49.5 

± 0.2 km/s (Kharchenko et al. 2007) to +51.6 km/s

Vol. 8 No. 2 April 1, 2012 


Page 136 


(Valenti & Fischer 2005). Other values: +49.6 ± 0.5 

km/s (Montes et al. 2001); +49.877 ± 0.222 km/s 

(Nidever et al. 2002); +49.7 ± 0.2 km/s (Gontcharov 

2006). For AB pair, the radial velocity in the literature 

range from +50.4 to +50.7 km/s and so AB and C 

has nearly the same radial velocity within error margins. 

I have used several tests (those of Dommanget 

(1955, 1956), Peter van de Kamp (1961) and Sinachopoulos 

& Mouzourakis (1992)) that are based on astromechanics. 

They are detailed in Benavides et al. 

(2010). The Dommanget test determined that C would 

be bound to AB if the stellar system is nearer than 

26.9 pc. Since the mean distance for AB and C is 

24.03 pc then, C could be bound to AB. The criterion 

of van de Kamp shows that the true critical value for 

a parabolic orbit is 236.9 AU 3 yr -2 while the observed 

projected critical value is of 118.2 AU 3 yr -2 , smaller 

than the true value, so it is possible that C is bound to 

AB. The tangential velocity corresponding to the observed 

relative proper motion for C with respect to AB 

is 2.0 ± 0.1 km/s. Using the criterion of Sinachopoulos 

& Mouzou, a maximum orbital velocity (circular and 

face-on orbit assumed) of 2.1 km/s was calculated so C 

could be bound to AB. In summary, the three tests 

agree in the physical relationship of C with AB. 

Using the expression obtained by Fischer & 

Marcy (1992) the expected semimajor axis is of 865 

UA (about 35.6 arcseconds) and the orbital period of 

~13,660 yrs (using the Kepler’s Third Law and assuming 

circular and face-on orbit). The arc covered by this 

component is only of 5.38 deg. If I consider this angular 

motion as the mean motion then, a complete orbit 

will be covered in about ~12,300 yrs. 

Burningham et al. (2009) used the method of Torres 

(1999) to obtain a relationship between ρ and a. 

They assumed random viewing angles (i.e. random 

inclinations) and an uniform eccentricity distribution 

between 0 < e < 1 to derive a relationship of 

then, the expected semimajor axis is 

And the orbital period is 

+ 0.91 

−0.36 

E( a) = ρ *1.10 

(2) 

+ 26.3 

E( 

a) 

= 31.8− 

10.4 

arc sec ≡ 772 

+ 639 

−253 

AU 

P ≅ 12,400 

+ 18,277 

−5,558 

years 

Search for New Bound Companions 

I search for unreported bound companions using 

SIMBAD and VizieR tools to find common proper motion 

pairs, consulting astrometric catalogs and photographics 

plates. If the target is a near one then I 

search for companions by plotting the neighbor stars 

in a color-magnitude diagram where apparent 2MASS 

J-K and K data are plotted. A dwarf sequence to the 

distance of the target is also plotted. Dwarf companion 

candidates must be located on or near this dwarf 

sequence. Subdwarf or white dwarf companions will 

be not detected unless I use reduced proper motion 

diagrams. Giant companions will be bright enough to 

be detected and they will be located well above the 

dwarf sequence. 

The expression of Abt (1988) which relates stellar 

masses of the primary with the maximum projected 

separation (in A.U.) was used to define the sky region 

to search. I selected our companion candidates consulting 

2MASS where only stars located within the 

search region and with a S/N > 10 were selected. 

Conclusions 

The increase of residuals for the last orbital solutions 

for WDS 02572-2458 (BU 741 AB), WDS 

02592+2120 (STF 333 AB), WDS 12158-2321 (BU 

920) and WDS 12463-6806 (R 207) indicated that a 

new revision was needed. The Thiele-Innes-van den 

Boss method and Docobo analytical method were used 

to determine new orbital elements. 

The orbit for STF333 is preliminary and very different 

from the orbit calculated by Coster (2009). In 

the next 10 years the difference in the ephemeris for 

rho is 0.03 - 0.04” so we should be able to determine 

in the next years which orbit is the nearest to the correct 

one. In this work theoretical isochrones confirm 

the subgiant nature for both members with an age of 

about 550-650 Myr, matching the age for its membership 

in the Ursa Major moving group. 

The new orbit of R 207 has a smaller period and 

semimajor axis than the previous orbit. In this work I 

estimate an age of about 100 Myrs. 

BU 920 shows clear and large residuals in the last 

years. The motion is large and rectilinear and the 

new orbit was very different from the previous orbit. 

Using evolutionary isochronal, I determined that the 

primary could be a slightly evolved star. 

The separation for BU 741 AB has started to close

Vol. 8 No. 2 April 1, 2012 


Page 137 


in the last years, increasing the residuals. The new 

orbit makes slight corrections to the previous orbit. In 

2012 the calculated relative radial velocity will be -9.1 

km/s, when the secondary is at 0.815 arcsec of angular 

distance. This would be a good time for the system 

to be observed spectroscopically. 

STF 333 AB has a wide optical component of 12.7 

magnitude and K0V spectral type. BU 741 AB has a 

bright physical companion (listed as S 423 C) of 7.84 

magnitude at a separation of 29”. The semimajor axis 

is about 772 AU and the orbital period is about 12,400 

years. 


This publication made use of the SIMBAD database 

and ALADIN tool, operated at the CDS in Strasbourg, 

France. The author thanks Brian Mason for 

his valuable advice and important support. The author 

is especially grateful to Andreas Alzner for the 

transmission of his knowledge about orbital calculations; 

without his help and patience I would not have 

enough skill and knowledge to calculate orbital parameters 

for visual double stars. 

I am kindly grateful to Clif Ashcraft for the English 

Grammar revision of this work. 

References 

Abt, H. A. 1988, ApJ, 331, 922 

Abt, H. A., & Morrell, N. I. 1995, ApJS, 99, 135 

Agüeros, M. A. et al. 2009, 181, 444 

Allen, C. W. 1973, Astrophisical Quantities, Athlone 

Press. 

Alzner, A. 1998, A&AS, 132, 237 

Alzner, A. 2003, Webb Soc., Double Star Circ. 11 

Alzner, A. 2005, Webb Soc., Double Star Circ. 13 

Anton, R. 2006, JDSO 2, 108 



Baize, P., & Romani, L. 1946, Ann. d’Astrophys., 9, 13 

Bartkevicius A., Gudas A., 2002, BaltA, 11, 153 

Beavers, W. I. & Eitter, J. J. 1986, ApJS, 62, 147 

Benavides Palencia, R., OAG Gen. Cat. 10.000 vis. 

double star meas. 1970-2003, (J2000.0), 2003 

Benavides, R., Rica, F., Reina, E., Castellanos, J., 

Naves, R., Lahuerta, L., Lahuerta, S. JDSO, 2010, 

6, 30 

Beuzit, J.-L. et al. 2004, A&A, 425, 997 

Bobylev V. V., Goncharov G. A., & Bajkova A. T., 

2006, ARep, 50, 733 

Burnashev V.I. 1985, Abastumanskaya Astrofiz. Obs. 

Bull. 59, 83 

Burningham et al., 2009, MNRAS, 395, 1237 

Burnham, S.W. 1883, MemRAS, 47, 167 

Burnham, S.W. 1887, PLicO, 1, 24 

Burnham, S.W. 1918, AJ, 31, 141 

Buscombe, W., & Foster, B. E. 1995, " 12th General 

Catalogue of MK Spectral Classification" Northwestern 

University, Evanston Illinois 

Caloi, R. M. 2008, JDSO 4, 111 

Catalán, S., Isern, J., García-Berro, E., Ribas, I., Allende 

Prieto, C., Bonanos, A. Z. 2008, A&A, 477, 

213 

Chiba, M. & Beers, T. C., 2000, AJ, 119, 2843. 

Christy, J. W., & Walker, R. L. Jr 1969, PASP, 81, 

643 

Comellas, J. L., OAG Gen. Cat. 10.000 vis. double star 

meas, 1970-2003. (J2000.0), 2003 

Corbally, C. J. 1984, ApJS, 55, 657. 

Coster, I. 2009, WSDSC, 17, 61 

Cowley, A., Cowley, C., Jaschek, M., & Jaschek, C. 

1969, AJ, 74, 375 

Cutri, R. N. et al., Explanatory to the 2MASS Second 

Incremental Data Release, 2000, http:// 

www.ipac.caltech.edu/2mass/releases/second/ 

index.html 

Da Silva et al., 2006, A&A, 458, 609 

Daley, J. A., 2003, Publ. Ludwig Schupmann Obs, #2 

Damiani, F., Micela, G., Sciortino, S., Harnden, F. R., 

Jr. 1995, ApJ, 446, 331 

Davis, J. & North, J. R. 2001, PASA, 18, 281 

Docobo, J. A. 1985, CeMec, 36, 143 

Docobo J. A., Balega, Y. Y., Ling J. F., Tamazian V. 

S., Vasyuk V. A., 2000, AJ, 119, 2422

Vol. 8 No. 2 April 1, 2012 


Page 138 


Docobo, J. A., & Ling, J. F. 2003, A&A, 409, 989-992 

Dommanget J., 1955, BAORB, 20, 1 

Dommanget J., 1956, BAORB, 20, 183 

Edwards, T. S. 1976, AJ, 81, 245 

Eggen, O. J. 1969a, PASP, 81, 741 

Eggen, O. J. 1969b, PASP, 81, 553 

ESA SP-1200, ESA Noordwijk, 1997, HIPPARCOS 

and TYCHO catalogs 

Favata, F., Micela, G., & Sciortino, S. 1997, A&A, 

323, 809 

Fischer D.A., Marcy G.W., 1992, AJ, 396, 178-194 

Girardi, L., Bressan, A., Bertelli, G., & Chiosi, C. 

2000, A&AS, 141, 371 

Gontcharov, G. A. 2006, AstL, 32, 759 

Gray, R. O., Garrison, R. F. 1987, ApJS, 65, 581 

Gray, R.O. et al. 2006, AJ, 132, 161 

Grenon , M. 1987, JAp&A, 8, 123 

Hartkopf, W. I. et al. 1989, AJ, 98, 3, 1014 

Hartkopf, W. I., Mason, B. D., Barry, D. J., McAlister, 

H. A., Bagnuolo, W. G., & Prieto, C. M. 

1993, AJ, 106, 352 

Heintz, W. D. 1978a, "Double Stars", (Dordrecht: D. 

Reidel Publishing Company, ISBN / EAN: 

9027708851 

Høg, E. et al. 2000, AJ, 355, 27 

Holmberg J., Nordstrom B., & Andersen J. 2009, 

A&A, 501, 941 

Horch, E. P., Davidson, J. W., Jr., van Altena, W. F., 

Girard, T. M., Lopez, C. E., Franz, O. G., & Timothy, 

J. G. 2006, AJ, 131, 1000 

Houk N. & Cowley A.P., 1975, Michigan Catalogue of 

Two-Dimensions. Vol. 1: Declinations from -90deg 

< δ < -53deg (Ann Arbor, Univ. of Michigan) 

Houk N., Smith-Moore M., 1988, Michigan Catalogue 

of HD stars, Vol.4, (Ann. Arbol: Univ. Michigan)) 

Irwin, A. W. et al. 1996, PASP, 108, 580-590 

Kaznica, J. J. 1994, Webb Soc., Double Star Circ. 6 

Kennedy, P. M 1983, MK Classification Extension, 

(Mt Stromlo & Siding Spring Observatories) 

Kharchenko, N. V., Scholz, R. D., Piskunov, A. E., 

Roeser, S., Schilbach, E. 2007, AN, 328, 889 

King, J. R., Villarreal, A. R., Soderblom, D. R., Gulliver, 

A. F., Adelman, S. J. 2003, AJ, 125, 1980 

Le Beau. J. 1987, OT, 9, 41 

Leeuwen, F. 2007, A&A, 474, 653 

Malaroda, S. 1975, AJ, 80, 637 

Mason, B. D. et al. 1999a, AJ, 117, 1023-1036 

McAlister, H. A. & Fekel, F. C. 1980, ApJS, 43, 327 

Montes D., López-Santiago J., Gálvez M. C., Fernández-Figueroa 

M. J., De Castro E., Cornide M., 

2001, MNRAS, 328, 45 

Mourao, R.F.F. 1964, Bull. R. Astron. Obs. Belgium 5, 

143 

Philip, A. Davis, Egret, D. 1980, A&AS, 40, 199 

Rica, F.M. 2008, RMexAA, 44, 137 

Rica, F.M. 2009, IAUDS, Inf. Circ. 169 

Rica, F.M. 2010, IAUDS, Inf. Circ. 172 

Rica, F.M. 2011, JDSO, 7, 114 

Russell, H. C. 1871-1881, Sydney Obs. Results 

Sartori, M. J., Lepine, J. R. D., Dias, W. S. 2003, 

A&A, 404, 913 

Scardia, M. 2002, IAUDS, Inf. Circ. 148. 

Seymour, D. et al. 2002, AJ, 123, 1023 

Sinachopoulos D. & Mouzourakis P., 1992, Complementary 

Approaches to Double and Multiple Star 

Research in the IAU Colloquium 135, ASP Conferences 

Series, Vol. 32 

Soderblom D. R., Mayor M., 1993, AJ, 105, 226 

South, J. 1826 Phil. Trans. R. Soc., 116, Pt.1 

Struve. F. G. W., Mensurae Micrometricae Petropoli. 

1837 

Tamazian, V. S., Docobo, J. A., White, R. J., & Woitas, 

J. 2002, ApJ, 578, 925 

Taylor, B. J. 2005, ApJS, 161, 444 

Tobal, T., OAG Gen. Cat. 10.000 vis. double star 

measurements, 1970-2003 , (J2000.0). 2003 

Tokovinin, A., Mason, B., & Hartkopf, W. 2010, AJ 

139, 743

Vol. 8 No. 2 April 1, 2012 


Page 139 


Torres G., 1999, PASP, 111, 169 

Urban, S. et al. 1998, AJ, 115, 1212, (Astrographic 

Cat. 2000) 

Valenti, J. A., Fischer, D. A. 2005, ApJS, 159, 141 

van de Kamp P., 1961, PASP, 73, 389 

Voges W. et al. 2000, IAU Inf. Circ., 7432, 1 

Wenger, M. et al. 2003, SIMBAD astronomical databa 

base, http://simbad.u-strasbg.fr/

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Naomi Warren 1 , Betsie Wilson 1 , Chris Estrada 2 , Kim Crisafi 1 , Jackie King 1 , 

Stephany Jones 1 ,Akash Salam 1 , Glenn Warren 1 , S. Jananne Collins 1 , and Russell Genet 3 

1. Arroyo Grande High School, CA 93420 

2. California State University, Los Angeles, CA 90032 

3. Cuesta College, San Luis Obispo, CA 93403 

Abstract: Members of a Cuesta College astronomy research seminar used a manuallycontrolled 

10-inch Newtonian Reflector telescope to determine the separation and position 

angle of the binary star Delta Cepheus. It was observed on the night of Saturday, October 

29, 2011, at Star Hill in Santa Margarita, California. Their values of 40.2 arc seconds and 

192.4 degrees were similar to those reported in the WDS (1910). 

Introduction 

The students of Cuesta College’s Astronomical 

Research Seminar made astrometric observations of 

Delta Cepheus (AC) on October 29, 2011, at Star Hill 

by Santa Margarita Lake in California, with a 10- 

inch, manually controlled Newtonian reflector. The 

equatorially-mounted telescope has a synchronous 

motor clock drive. The telescope was built by an amateur 

astronomer and refurbished by Chris Estrada. 

Drift Time 

The drift time was determined by orienting the 

eyepiece with the celestial coordinates. Once orientation 

was completed, we aligned the star, Alpheratz, 

at one end of the linear scale, turned off the right 

ascension motor, and determined the time it took for 

this star to travel to the other end of the linear scale. 

The time was recorded when the star was bisected by 

the last division mark. 

The mean value for the drift time (Table 1) was 

used to calculate the scale constant, which was subsequently 

used to determine the separation in arc 

seconds. The scale constant was determined by the 

equation . 

Figure 1: The observing team. Top left to right: Chris Estrada, 

Glenn Warren, Russ Genet. Bottom left to right: Kim Crisafi, 

Naomi Warren, Betsie Wilson, Stephany Jones, and Jackie King 

Table 1: Data for the drift time; twelve measurements 

were made. 

Drift time (seconds) 

Mean 61.3 

Standard Deviation 0.7 

Standard Error of the Mean 0.2

Vol. 8 No. 2 April 1, 2012 


Page 141 


15.0411tcos( d) 

Z = 

D 

where Z is the scale constant in arc seconds per division, 

15.0411 is the number of arc seconds per second 

of the Earth’s rotation, t is the average drift time in 

seconds, d is the declination of the star, and D is the 

number of divisions on the linear scale (60). 

Separation and Position Angle Observations 

The distance between the binary stars was estimated 

by each observer to the nearest tenth of a scale 

division. Angular separation was determined by multiplying 

the mean of the distances by our measured 

scale constant of 11.5 arc seconds per division. The 

separation was estimated twice by each of six observers 

for a total of twelve values. 

The position angle was found by placing the 

brighter binary star at the center of the eyepiece, 

then aligning the eyepiece so that the linear scale bisected 

both stars, then turning off the synchronous 

motor and observing and recording point at which the 

star crossed the inner protractor. Results of the measurements 

are in Table 2. 

Discussion and Conclusion 

We estimated the separation to be 40.2 arc seconds, 

which compared favorably with the value of 

Table 2: Data for the separation and position angle; twelve 

measurements were made for both separation and position 

angle. 

40.7 arc seconds reported in 2010 in the Washington 

Double Star Catalog. Our position angle was measured 

as 192.4 degrees which also compared favorably 

with the last observation recorded in the Washington 

Double Star Catalog which found the position angle to 

be 191 degrees. 

Acknowledgment 

We thank John Baxter and Vera Wallen for their 

outside reviews of our paper. 

Reference 

Separation 

(arc seconds) 


(degrees) 

Mean 40.2 192.4 

Standard Deviation 4.5 1.8 

Standard Error of the Mean 1.1 0.5 

Mason, Brian, 2007, The Washington Double Star 

Catalog. Astrometry Department, U.S. Naval 

Observatory.

Vol. 8 No. 2 April 1, 2012 


Page 142 

Astrometric Measurements of Selected Visual 

Double Stars 

Jonathan Boyd 1 , Anthony Brokaw 1 , Jackie Deventer 1 , Monica Garcia’, Mario Gastelum 1 , 

Yvelisse Guerrero 1 , Joy Hallett 1 , Kelli Heape 1 , Margarita Ibarra 1 , Richard Langston 1 , 

Dawn Maddux 1 , Jack Moreland 1 , Randall Mozzillo 1 , Jason Overholts 1 , Kevin Perez 1 , 

Valorie Randle 1 , Samantha Savard 1 , Mike Stewart 1 , Lajeana West 1 , 

Angela McClure 2 , Douglas Walker 3 

1. Students in Astronomy 111 and Mathematics 298AA 

2. Faculty, Mathematics, Astronomy and Physics 

3. Adjunct Faculty, Mathematics and Astronomy 

Estrella Mountain Community College 

Avondale, Arizona 

Abstract: The observations and measurements for a selected set of 13 double stars are reported. 

These tasks comprised the activities in a special course designated as a Learning 

Community which combines a standard astronomy course with a mathematics course devoted 

to research techniques. This class was taught at the Estrella Mountain Community 

College in Avondale, Arizona during the fall semester 2011. This course is a result of expanding 

the special research mathematics courses offered during the fall 2010 and spring 

2011 semesters. Observations and measurements were taken with a Meade 12” Schmidt 

Cassegrain Telescope (SCT) using the Celestron MicroGuide TM and supplemented with imagery 

acquired with the Tzec Maun Foundation remote telescope system located in New 

Mexico. 

Introduction 

This observation program is part of a special 

combination introductory astronomy and mathematics 

course dedicated to teaching research techniques 

and applied mathematics. Astronomy course AST 

111 which is an introduction to astronomy for nonscience 

majors was combined with mathematics 

course MAT 298 AA which provides the opportunity 

for independent study to create what is called a 

Learning Community (LC). The general goal of this 

LC was to provide a greater depth of science exposure 

than could be achieved in either the astronomy 

or mathematics course alone. Specific objectives for 

the LC was to expose the students to real-world application 

of mathematics in the process of observing 

and reducing data taken under less than ideal conditions. 

These same approaches and data techniques 

are widely used in a variety of professional fields and 

applications. 

The observational areas chosen were the visual 

measurements of double stars. The selection of stars 

for observation and measurement were taken from 

the Washington Double Star Catalog (WDS), a webbased 

repository for double and multiple star information. 

The selection of researching binary stars was 

chosen since the observation and measurements of 

double star systems are an area which can be 

achieved with the use of small telescopes. [1] 

Instrumentation: Meade 12” LX200 

The instrumentation used for observations and 

measurements consisted of a Meade 12” LX200GPS 

f/10 Schmidt-Cassegrain telescope. This system is an 

azimuth type system featuring automatic calibration 

and GPS location. The GPS feature made initial

Vol. 8 No. 2 April 1, 2012 


Page 143 


setup and calibration fast and easy. Double star 

measurements were obtained using the Celestron MicroGuide 

eyepiece which is a 12.5 mm F/L Orthoscopic 

with a reticule and variable LED. 

All visual observations were taken on the campus 

of Estrella Mountain Community College campus located 

at 33 o 28’49.46”N, 112 o 20’36.47”W during evening 

hours which generally consisted of between 7:00 

and 10:00 PM local time (02:00 to 05:00 UT). Observations 

and measurements covered the dates from mid 

September 2011 through late November 2011. 

Tzec Maun Remote Telescope 

The Tzec Maun Foundation is a non-profit foundation 

which strives to provide students from all over 

the world with access, through teachers and professors, 

to astronomical instruments that can be easily 

incorporated into the classroom and even used from 

home. The foundation allows students to access quality 

telescopes in the northern and southern hemispheres, 

providing a view of the entire sky from locations 

in New Mexico and Australia. Accesses to the 

remote telescopes were utilized to image selected double 

star targets in order to contrast visual observations 

with image analysis. 

Several telescope systems were available for advanced 

reservation and use. The system chosen was 

the Takahashi Epsilon 180 with an f/2.8 focal length 

(Figure 1). These setups are typically reserved for beginners 

only. The E180s has a ST-2000C camera as 

it’s imaging system. This provides a field of view of 

80.5 x 60.4 arcminutes with a pixel count of 1600 x 

Figure 1: Takahashi Epsilon 180 f/2.8 

1200 providing an image scale of 3.02"/pixel 

(arcseconds per pixel).This camera system provides a 

JPEG image - there is no FITS file for data. A fullrange 

and an adjusted (processed) image of each shot 

are provided. 

Research Teams 

In order to maximum the individual student’s observing 

time, the class was broken up into observation/research 

teams. Teams were the best option as 

having the entire class observing simultaneously 

would have limited the amount of stars able to research, 

while individually would prove to be too time 

inefficient. Teams were chosen at the beginning of the 

semester based on the number of students enrolled. 

Initially, the class was divided into five teams of 3-4 

students. As the semester progressed, due to normal 

student attrition, the class finally settled into four 

teams for maximum time efficiency. Teams would rotate 

on an approximate hourly basis with each team 

getting one hour per rotation to gather observational 

data. Each rotation was completed by two class periods. 

Teams proved to be flexible due to the fact team 

members could compare individual measurements 

and share workloads. Participants in the project are 

shown in Figure 2. 

Selection of Stars 

The selection of stars for observation and measurement 

were taken from the WDS Catalog, a webbased 

repository for double and multiple star information. 

The WDS is maintained by the United States 

Naval Observatory and is the world's principal database 

of astrometric double and multiple star information. 

The WDS Catalog contains positions (J2000), 

discoverer designations, epochs, position angles, separations, 

magnitudes, spectral types, proper motions 

and when available, Durchmusterung numbers and 

notes for the components of 108,581 systems based on 

793,430 means. The current version of the WDS is 

updated nightly. The selection of target stars resulted 

from reviewing the list of both common observed and 

neglected double stars referenced on the WDS main 

web page. 

In order to try and provide observational coverage 

of the widest range of double stars, the selection of 

target stars off the WDS website assigned to a research 

team consisted of the target star row location 

in the database corresponding to the research team 

identification number. For example, Team 1 candidate 

target list consisted of stars in rows 1, 6, 11, etc. 

Team 2 had candidates in rows 2, 7, 12, etc. This ap-

Vol. 8 No. 2 April 1, 2012 


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Figure 2: Fall 2011, Astronomy and Mathematics Learning Community 

proach provided an even distribution of target stars 

across the WDS list in the appropriate right ascension 

location. 

The actual selection of the stars for attempted 

observation was a critical step to the measurement of 

the binary star systems. In order to select stars off 

the WDS catalog, a series of specific guide lines were 

established and followed. The magnitude of the primary 

and secondary stars had to be less than magnitude 

8, anything greater was not visible through the 

telescope with the current observing location and conditions. 

The separation measurement was also a selection 

criteria in that the separation had to also lie 

between 7 and 200 arc seconds. The limitation of 7 arc 

seconds was a hard constraint due to only being able 

to measure about 1 separation hash mark on the MicroGuide 

eye piece. This corresponds to approximately 

7.43 arc seconds. Finally, the right ascension 

and declination coordinate had to be appropriate for 

location and the time of observing. [2] 

Visual Measurements of Selected Binary 

Stars 

Measurements of the separation distance and position 

angle of the selected binaries was accomplished 

using a standard visual observational approach. In 

order to produce high quality measurements, care 

was taken in calibrating the measurement instrument 

by performing a series of test measurements for 

validation of results before proceeding to the measurements 

of the target stars. 

MicroGuide Calibration 

As performed in the previous two semesters of 

observing double stars, the technique for calibrating 

the MicroGuide was the standard star drift method. 

The calibration process was carried out using measurement 

data collected by each team and combining 

results for an average measure. The star used for calibration 

measurements was Vega at coordinates 18h 

36m 56.33s, +38 0 47’ 01.28”. 

Using a stopwatch, each team member timed the 

transit of Vega from one edge of the MicroGuide scale 

to the opposite edge. This process was repeated five 

times by each team member. After the measurements 

were taken, the data was collected and an average 

time of 38.139 seconds was arrived from the total 

number of measurements with a standard deviation 

of 1.544 seconds. Next a plot of the histogram was 

generated and using the standard deviation of 1.544 

seconds, outliers were identified and removed that fell 

outside a ± one standard deviation range. Using the 

adjusted average time in the formula “SC = Avg Time 

* Cos (Dec) / 4”, the class calculated that the scale 

constant to be 7.427 arc seconds per MicroGuide division. 

This scale constant was used to measure the 

separation distance between the binary stars chosen 

by each group. [3] 

The histogram of the timing measurements for 

Vega drift rates is shown in Figure 3. These measurements 

are contrasted against those taken in the fall 

2010 and spring 2011 semesters. Drift measurements 

were averaged to produce the calibration for the same 

observing system for the fall 2010 which resulted in 

an average of 38.26 seconds per drift. The corresponding 

histogram is shown in Figure 4. The separation 

was calculated to be 7.26 arc seconds. 

The process was repeated for spring 2011 which

Vol. 8 No. 2 April 1, 2012 


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12 

10 

8 

Frequency 

6 

4 

2 

0 

31 31. 2 31.4 31.6 31.8 32 32.2 32.4 32.6 32.8 33 33.2 33.4 

Seconds per Drift 

Figure 3: Histogram of Timing Measurements for Fall 2011 

Figure 5: Histogram of Timing Measurements for Spring 

2011 

Frequency 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

37 37.2 37.4 37.6 37.8 38 38.2 38.4 38.6 38.8 39 39.2 

Seconds per Drift 

Figure 4: Histogram of Timing Measurements for Fall 2010 

Table 1: Summary Results for MicroGuide Calibration 

Drift Measurement 

(sec) 

Scale 

(arcsec) 

Period Average 1 STD Average 

Fall 2010 38.26 0.38 7.26 

Spring 2011 32.21 0.43 7.39 

Fall 2011 38.14 1.54 7.43 

resulted in the histogram shown in Figure 5 with a 

mean drift time of 32.21 seconds. Based on the timing 

average, a separation between scale divisions was 

calculated to be 7.39 arc seconds. 

A review of the progression of the scale factor over 

three semesters of measurements is shown in Table 1. 

Notice that the arcsec distance for a MicroGuide division 

has been increasing. No apparent reason for the 

lengthening of the drift was found. 

Measurements Process 

As in the previous semesters observing sessions, a 

round robin technique was utilized for taking new 

measurement data. Separation was measured by orienting 

the selected double star systems along the Microguide’s 

linear scale, and noting their separation as 

indicated by the scale’s division marks. Position angle 

was then measured by aligning the binary systems 

along the linear scale, with the primary star directly 

on mark 30, and the secondary along the scale between 

marks 30 and 60. After the stars were aligned, 

the telescope’s tracking system was temporarily disabled, 

allowing the binary system to drift out of the 

eyepiece’s field of view. The binary system crossed 

over the circular scale which runs along the edge of 

the telescope’s FOV, as this happened the position of 

the secondary star along this circular scale was noted. 

These processes were repeated several times per system 

for separation accuracy. Summary of measurement 

data are shown in Table 2.

Vol. 8 No. 2 April 1, 2012 


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Table 2: Summary Data for Measures Fall 2011 

WDS ID 

Discover 

Magnitudes Last Current 

Primary Sec Epoch PA SEP Epoch PA SEP 

21543+1943 STF2841A,BC 6.45 7.99 2010 110 22.3 2011.965 114 22.3 

20136+4644 STFA 50AC 3.93 6.97 2008 174 106.7 2011.965 174 111 

22038+6438 STF2863AB 4.45 6.4 2010 275 8 2011.957 267 6.9 

18562+0412 STF2417AB 4.59 4.93 2010 104 22.4 2011.764 99 24.7 

21069+3845 STF2758AB 5.2 6.05 2010 152 31.4 2011.778 175 34.2 

19050-0402 SHJ 286 5.52 6.98 2010 210 41.5 2011.835 210 38.2 

20375+3134 STFA 53AB 6.29 6.54 2003 177 182.7 2011.835 185 187.3 

19418+5032 STFA 46AB 6 6.23 2010 141 39.7 2011.822 310 51.3 

20467+1607 STF2727 4.36 5.03 2010 266 9 2011.778 280 12.1 

20302+1925 S 752AC 6.8 7.3 2001 288 106.7 2011.797 330 111.0 

12492+8325 STF1694AB 5.29 5.74 2008 236 21 2011.823 235 29.2 

15292+8027 STF1972AB 6.64 7.3 2010 169 31.4 2011.874 165 37.3 

21287+7034 STF2806AB 3.17 8.63 2009 250 14.1 2011.879 256 14.8 

Measurements of Selected Binary Stars 

using Tzec Maun Remote Telescope 

Background 

The Tzec Maun Takahashi Epsilon 180 remote 

telescope system was used to determine the utility of 

utilizing a remote system to perform measurements 

on double star systems. Each team selected one star 

from their target list to image and then perform an 

analysis on the measured separation distance. Due to 

time constraints, only separation distances between 

the primary and secondary stars were measure and 

compared. The image analysis package used was the 

ImageJ. ImageJ is a public domain, Java-based image 

processing program developed at the National Institutes 

of Health. ImageJ was designed with an open 

architecture that provides extensibility via Java 

plugins and recordable macros 

Calibration of Imagery 

Σ2470 and Σ2474 is known as the Double-Double’s 

double located in the constellation Lyrae. Lying 

southeast of Epsilon Lyrae, the system consists of two 

similarly bright double stars set approximately 10 

arcminutes apart. Both double star systems have 

nearly identical separations and position angles. 

Σ2474 was chosen as the double star used for calibration 

being located at 19h 09.1m RA and +340 36’ Dec. 

[4] 

The image of Σ2474 taken with the Takahashi 

Epsilon 180 and ST-2000C camera is shown in Figure 

6. 

Based on utilizing the double star set with the 

known separation of 16 arc seconds, a scale factor of 

0.0999 arc secs per ImageJ linear pixel measurement 

was derived. This value was then used to measure the 

separation distance of the target stars. 

Figure 6: Σ2474 used as Calibration Double Star

Vol. 8 No. 2 April 1, 2012 


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Comparisons of Measurement Results 

between Visual and Remote Telescope 

Each team selected one star from their observing 

list to perform a comparison. The largest task turned 

out to be locating the target stars on the imagery. 

Various techniques were employed to match up the 

observed stars with imagery including going back to 

the telescope to confirm the visual field. The most 

productive approach was to image the selected area 

with varying exposure times and then comparing imagery 

to locate the target stars. 

Individual team assessments and comparisons 

are given below. 

Team 2 

Team 2 selected the double system STF2863AB 

(R.A: 22h 03m 47s DEC: +64d 37m 39s) for comparison 

analysis. The averaged separation distance for 

STF2863AB was measured as 6.9 arc seconds. Figure 

7 below shows the images of the same stars taken 

with the remote online telescope. Using the ImageJ 

software, the amount of pixels in the line was obtained 

and using the conversion factor of approximately 

0.0999, a measured separation distance of 7.9 

arc seconds was acquired. The last measurement 

documented was taken in 2010 and indicated a separation 

distance of 8 arc seconds. The difference could 

be due to the fact that the eyepiece used was measure 

in 7.43 arc seconds per MicroGuide division mark 

which created a slight deviation compared to the remote 

telescope imagery measurements. The initial 

image showing a FOV of 80.5 x 60.4 arc minutes is 

shown in Figure 7 with an enlargement and separation 

measurement between the primary and secondary 

star shown in Figure 8. 

Team 3 

Team 3 initial list of stars proved difficult for initial 

observation. Five attempts were tried before the 

first star. STF1694AB (RA: 12h 49m 13.80s DEC: 

+83d 24m 46.3s) was located. Once the star was verified 

as being the target star, 15 measurements using 

the telescope were obtained. Once all team members 

took measurements, the mean was obtained and multiplied 

by the calibrated conversion factor to obtain 

28.93 arcseconds on the star. References in the WDS 

database indicated that the star had a measured 

separation of approximately 21 arc secseconds. The 

difference was attributed to lack of experience. With 

the learning curve behind the team, the next two 

stars measured were nearly dead on. The image taken 

with the Takahashi Epsilon 180 for STF1694AB is 

Figure 7: STF2863AB 

Figure 8: ImageJ Measurement of STF2863AB 

Figure 9: STF1694AB

Vol. 8 No. 2 April 1, 2012 


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shown in Figure 9 and in addition to the binary stars 

of interest, showed many additional stars. After some 

additional work, the stars of interest were located and 

measuring the star separation (Figure 10) by pixeland 

utilizing the conversion factor of .0999 arcseconds per 

pixel, the separation distance matched up perfectly. 

Team 5 

Team 5 took a total of 20 measurements with the 

Meade 12” LX200GPS f/10 Schmidt-Cassegrain telescope 

on October 27, 2011. Each team member took 5 

measurements, rotating out, one at a time. We averaged 

a separation distance of 6.9 arc seconds for the 

binary stars STFA46AB (R.A: 19h 41m 48s DEC: + 

50d 32m 0s). The initial images of the same stars 

taken with a Takahashi Epsilon 180 telescope is 

shown in Figure 11. Using image software, ImageJ, 

we calculated the amount of pixels in the line between 

the stars using a conversion factor of approximately 

0.0999 arcseconds per pixel. We measured a separation 

distance of 3.82 arc seconds with the image software 

(Figure 12). We realized this was a significant 

difference so we measured again with the Meade 12” 

LX200GPS f/10 Schmidt-Cassegrain telescope and got 

the same result. We cannot account for the difference 

between the Meade 12” LX200GPS f/10 Schmidt- 

Cassegrain telescope and the Takahashi Epsilon 180 

but we made numerous attempts to verify our measurements. 

Team 4 obtained very accurate visual measurements 

of four double stars, but had difficultly locating 

the target stars in the Takahashi Epsilon 180 imaging. 

The lack of access back to the remote telescope 

forced the team not to be able to obtain imagery of the 

stars of interest; hence, their analysis is not included. 

Results of Comparison Analysis 

An analysis of the separation distances between 

selected double stars described by the individual 

teams above is shown in Table 2. It is clearly shown 

that the accuracy of using an online remote telescope 

system to obtain measurements of double star systems 

can be quite feasible. It also demonstrates the 

difficultly of obtaining the correct stars for measurement 

and if care is not taken, erroneous measurements 

can result. 

Conclusion 

These observations provide additional information 

for researchers to investigate the nature of binary 

systems. 

Figure 10: ImageJ Measurement of STF1694AB 

Figure 11: STFA46AB 

Figure 12: ImageJ Measurement of STFA46AB

Vol. 8 No. 2 April 1, 2012 


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Table 2: Comparison of Observed and Imaged Measures 

Separation – Arcseconds 

Star WDS Observed Imaged 

Arcsec Difference 

to WDS 

STF2863AB 8 6.9 7.9 0.1 

STF1694AB 21 28.9 21 0 

STFA 46AB 39.7 51.3 38.2 35.9 


We would to thank Estrella Mountain Community 

College for latitude in using equipment and facilities 

and especially the Tzec Maun Foundation for access 

to their remote telescope systems. 

References 

1. Ronald Charles Tanguay, "Observing Double Stars 

for Fun and Science", Sky and Telescope, 116-121, 

February 1999. Retrieved 17 July 2011 from website: 

http://www.skyandtelescope.com/observing/ 

objects/doublestars/3304341.html 

2. Northern Hemisphere Sky Chart, Sky and Telescope 

Magazine, October 2011, page 44 

3. The Celestron Micro Guide Eyepiece Manual 

(#94171) 

4. James Mullaney, Double Stars of Summer, Sky and 

Telescope Magazine, July 2011, page 40

Vol. 8 No. 2 April 1, 2012 


Page 150 

Measurements of Beta Lyrae at the Pine 

Mountain Observatory Summer Workshop 2011 

Joseph Carro 

Cuesta College, San Luis Obispo, California 

Rebecca Chamberlain 

Evergreen State College 

Marisa Schuler, Timothy Varney 

Evergreen High School 

Robert Ewing 

Portland Community College 

Russell Genet 

Cuesta College, San Luis Obispo, California 

California Polytechnic State University, San Luis Obispo, California 

Abstract: As part of the Pine Mountain Observatory Summer Workshop 2011, high school 

and college students joined with an experienced observer to learn the use of a telescope, astrometric 

techniques, and measure a double star. This workshop was the first time these 

students operated a telescope, and, thus, constituted an educational experience for them as 

they used the telescope and took the measurements. The double star Beta Lyrae was 

measured resulting in a separation of 44.3 arc seconds and a position angle of 151.6 degrees. 

The Washington Double Star catalog (2009 data) lists a separation of 45.4 arc seconds 

and a position angle of 148 degrees 

Introduction 

Beta Lyrae was first determined to be a double 

star by John Goodricke in 1784. Beta Lyrae has 

catalog designations of 10 Lyrae, AAVSO 1846+33, 

BD+33°3223, FK5 705, HD 174638, HIP 92420, 

HR 7106, SAO 67451, and WDS 18501+3322. Its 

traditional name is Sheliak. Its precise coordinates 

as given by the Washington Double Star Catalog are 

185004.79+332145.6. 

This double star is located at the southwestern 

tip of the parallelogram that makes the body of 

the Harp, and is referred to as Sheliak, an Arabic 

word that means “harp”. Sheliak is a spectroscopic 

binary whose proximity is such that the two stars 

constantly distort each other and constitute an 

eclipsing binary. Sheliak's variations are visible to 

the naked eye, and were discovered in 1784. 

The two goals of this project were to 1) measure 

the position angle and separation of the aforementioned 

double star, and 2) learn the necessary 

techniques to conduct this research. 

Observations 

The observations were made using a Celestron 

model CPC 1100 telescope. This telescope is computerized 

and motorized and was fitted with a Celestron 

12.5 mm astrometric eyepiece. The telescope is of 

Schmidt-Cassegrain design, with aperture of 11 

inches and a focal length of 2,800 mm. 

Following the procedure provided by Celestron 

Corporation, the Micro Guide eye piece was oriented 

with the celestial coordinate system using the primary 

star of the double star Beta Lyrae. Once the

Vol. 8 No. 2 April 1, 2012 


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Measurements of Beta Lyrae at the Pine Mountain Observatory Summer Workshop 2011 

orientation was completed, 12 drift time measurements 

were made, with an average value of 33.54 seconds, 

and a standard deviation of 0.335 seconds. That 

average was used to calculate the scale constant using 

the formula Z = 15.0411 times T average times the 

cosine (0.83581) of the declination angle (33.30 o ) divided 

by 60 (the number of reticle divisions) as given 

by Frey (2008). 

15.0411T ave cos( δ ) 

Z = 

D 

The result was a scale constant of 7.02 arc seconds 

per division. 

The primary star was placed on the linear 

scale, and 10 separation measurements were taken. 

The primary star was relocated and advanced on the 

linear scale prior to each measurement. The average 

value was 6.3 with a standard deviation of 0.26 and a 

standard error of the mean of 0.08. The average 

value was used to calculate the separation, which was 

44.3 arc seconds. 

The position angle measurements were made 

by aligning both stars on the linear scale with the primary 

star at the 30 o division, disabling the tracking 

feature, and then allowing the stars to drift to the 

Table 1: Our measurements and some past published 

measurements of β Lyrae. 

Reference 

Separation Position Angle 

arc seconds 

degrees 

WDS (Mason+ 2007) 1777 

data 

48.9 143 

SKY2000 Master Catalog 

(Meyers+ 1994) 

45.7 149 

Stargazer 

(richardbell.net) 1996 

46 149 

Double Stars 

(Haas 2008) 2002 data 

46 150 

Eagle Creek Observatory 

(Muenzler) 2003 

46.6 149 

JDSO (Muller) Spring 

2007 

47.4 150.5 

JDSO (Muller) Winter 

2007 

46.4 148.8 

WDS (Mason + ) 2007 48 148 

JDSO (Arnold) 2009 45.5 149.9 

JDSO (Martín) Winter 

2009 

45.6 148 

WDS (Mason+ 2011) 2009 

data 

45.4 148 

Tycho Catalog 2011 45.7 148.5 

Our measurements 2011 44.3 151.6 

circular scales. The crossing of the primary star at 

the inner scale was approximated to the nearest degree 

as the scale has divisions of 5 o . Following each 

measurement, the tracking feature was enabled and 

the process was repeated. 

On 26 July 2011 beginning at 10:40pm PDT, position 

angle measurements were taken. Due to winds 

and fog, only seven measurements were taken with 

an average value of 151.6 o , a standard deviation of 

2.3 o , and a standard error of the mean of 0.86 o . Our 

results plus some historical measurements are given 

in Table 1. 

Conclusions 

The position angle average and the separation of 

the double star Beta Lyrae were successfully measured. 

An understanding of the time and effort to 

learn the techniques to accomplish these tasks was 

imparted to the participants, and it is deemed that 

the goals of the project were met. 


Heartfelt appreciation is extended to Russell 

Genet for his professional guidance and instruction in 

the completion of this project. We were appreciative 

of the efforts made by Thomas Frey in his management 

of the Workshop. Our team is grateful to the 

University of Oregon and the staff at the Pine Mountain 

Observatory for the use of their facilities, and to 

John Baxter for his review of this paper. 

References 

Arnold, D. “Divinus Lux report #16”, Journal of Double 

Star Observations, vol. 5 no. 1 Winter 2009 

Daley, J., 2006, “Double Star Measures for the year 

2005”, The Journal of Double Star Observations, 

vol 2 no 2 Spring 2006 

Frey, Thomas, 2008, “Visual Double Star Measurement 

with an Alt-Azimuth Telescope”, Journal of 

Double Star Observations, vol 4 no 2 Spring 2008 

Haas, S. 2008, “Double Stars for Small Telescopes”, 

Sky Publishing Corporation 

Hoffleit, D. and Warren, W., 1991, The Bright Star 

Catalogue, 5th Revised Edition, Yale University 

Martín, E, “CCD Double Star Measurements), Journal 

of Double Star Observations, vol. 5 no. 1 Winter 

2009

Vol. 8 No. 2 April 1, 2012 


Page 152 

Measurements of Beta Lyrae at the Pine Mountain Observatory Summer Workshop 2011 

Mason, B., Wycoff, G., Hartkopf, W., Douglass, G., 

Worley, C., 2010, Washington Double Star Catalog 

Muller, R., Cerosimo, J., Miranda, V., Martinez, C. 

Carrion, P., Cotto, D. Rosado-de Jesus, I. Centeno, 

D. Rivera, L., “Observation Report 2003-2004”, 

Journal of Double Star Observations, vol. 3 no. 1 

Winter 2007 

Muller, R., Cerosimo, J., Miranda, V., Martinez, C., 

Cotto, D. Rosado-de Jesus, I. Centeno, D. Rivera, 

L. “Observation Report 2005”, Journal of Double 

Star Observations, vol. 3 no. 2 Spring 2007 

Tycho Catalogue, 2011 from its website 

www.rssd.esa.int

Vol. 8 No. 2 April 1, 2012 


Page 153 

Visual Astrometry Observations of the Binary 

Star Beta Lyrae 

S. Jananne Collins 1 , Kyle M. Berlin 1 , Clare E. Cardoza 1 , Chris D. Jordano 1 , Tatum A. 

Waymire 1 , Doug P. Shore 1 , John Baxter 1 , Robert Johnson 1 , Joseph Carro 2 , and Russell 

M. Genet 2 



Abstract: Students from Arroyo Grande High School and Cuesta College observed the separation and 

position angle of the binary star Beta Lyrae (WDS 18501+3322 ). The separation and position angle were 

found to be 46.7 arc seconds and 149.6° respectively. These values compared favorably to past observations. 

Introduction 

Beta Lyrae was first observed in 1777 (Mason, 

2011). We determined its current separation and position 

angle as a part of the fall 2011 Astronomy Research 

Seminar at Cuesta College’s South Campus in 

Arroyo Grande, CA. This was the fifth year this 

seminar was held at Arroyo Grande High School and 

we built on the experiences of past student projects 

(Alvarez et al., 2009; Marble et al., 2008). Visual observations 

are relatively easy to make, and thus are 

well suited to novice researchers. Seven student observers 

joined telescope owner Joseph Carro on July 

2, 2011 at Santa Margarita Lake to observe β Lyrae. 

Procedure 

The observations were made with an 11 inch Celestron 

model CPC 1100 telescope of Schmidt- 

Cassegrain design and 2,800 mm focal length to determine 

the separation and position angle of Beta 

Lyrae. This telescope is computerized and motorized, 

and was fitted with a Celestron 12.5 mm Micro 

Guide astrometric eyepiece. 

Figure 1: From left to right, Kyle Berlin, Sarah Collins, Joseph 

Carro, Chris Jordano, Clare Cardoza, and Tatum Waymire 

For calibration, the linear scale was oriented east 

-west with the celestial sphere by slewing the telescope 

east and west and rotating the eyepiece until 

the primary star of Beta Lyrae did not deviate from

Vol. 8 No. 2 April 1, 2012 


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the linear scale. The date for the calibration was obtainted 

by aligning the primary star at one end of the 

linear scale, turning the right ascension motor off, 

and determining the time it took for the star to travel 

to the other end of the linear scale. 

Thereafter, the scale constant was determined by 

the equation below, where Z is the scale constant in 

arc seconds per division, 15.0411 is the number of arc 

seconds per second of the Earth’s rotation, t is the 

average drift time in seconds, d is the declination of 

the star, and D is the number of divisions on the linear 

scale (60) (Frey, 2008): 

Table 2: Data for Position Angle and Separation 

Separation (as) Position Angle (deg) 

Mean 46.7 149.6 

St. Dev. 0.3 0.8 

St. Error 0.7 3.7 

Z 

= 

15.0411 t cos( d) 

D 

Eleven position angle measurements were made 

by aligning both stars on the linear scale with the primary 

star on the 30 division, disabling the tracking 

feature and allowing the primary star to drift across 

the eyepiece. The point at which the primary star intersected 

the inner protractor was estimated to the 

nearest degree. After each measurement, the tracking 

feature was enabled and the process repeated. 

The separation was determined by placing the 

primary star on the linear scale, and estimating the 

scale divisions between the two stars. This process 

was repeated a total of twelve times. 

Scale Constant 

Four team members conducted four drift time 

measurements each, resulting in a total of sixteen 

measurements. The scale constant was calculated by 

the procedures described above. The results are 

shown in Table 1. Included are drift time, the mean, 

standard deviation, and the standard error of the 

mean, calculated by Microsoft Excel. The scale constant 

was found to be 7.17 arc seconds per division. 

Separation and Position Angle 

The objective of observing the binary star Beta 

Lyrae was to determine the current separation and 

position angle between the two stars. In order to 

avoid bias, three team members whispered each 

measurement privately to the recorder so as to not 

influence the other team members. However, the eyepiece 

was not repositioned after each observation, 

which may have resulted in systematic error. Table 2 

indicates the mean, standard deviation, and standard 

error of the mean for separation and position angle. 

The calculations were completed using Microsoft Excel. 


The data compares favorably with historical observations. 

The position angle was found by our observations 

to be 149.6°, while the mean of all past observations 

reported in the Washington Double Star 

Catalog is 148.9°. In terms of separation, we concluded 

it is currently 46.7 arc seconds, whereas the 

mean for all 102 WDS observations states it is 46.3 

arc seconds (Mason, 2011). A plot of previous observations 

compared to our data is shown below in Figures 

2 and 3. 

Table 1: Drift Time data for the primary star 

Drift Time (secs) 

Mean 31.5 

St. Dev. 1.7 

St. Error 1.4 




Observatory. We would like to thank Brian Mason for 

his help in providing past observations. We also 

thank the external reviewers Jordan Fluitt, Akash 

Salam, and Betsie Wilson for their help in editing the 

paper. 


Vol. 8 No. 2 April 1, 2012 


Page 155 


Figure 2: Our separation measurements compared to historical observations 

Figure 3: Our position angle measurement compared to historical observations

Vol. 8 No. 2 April 1, 2012 


Page 156 



References 

Alvarez, P. et al. 2009, “A Comparison of the Astrometric 

Precision and Accuracy of Double 

Star Observations with Two Telescopes”, Journal of 

Double Star Observations, vol.5 

no.1. 

Frey, Thomas, 2008, “Visual Double Star Measurement 

with an Alt-Azimuth Telescope”, 

Journal of Double Star Observations, vol. 5 no. 1. 

Marble, S. et al. 2008, “High School Observations of 

the Visual Double Star 3 Pegasi.” 

Journal of Double Star Observations, vol. 4, no. 25. 

Mason, Brian, 2011, The Washington Double Star 

Catalog. Astrometry Department, U.S. 

Naval Observatory.

Vol. 8 No. 2 April 1, 2012 


Page 157 


Jordan Fluitt 1 , Everett Heath 1 , Bobby Johnson 1 , Grayson Ortiz 1 , 

Hollie Charles 1 , Reed Estrada 3 , and Russell Genet 2 



3. Central Coast Astronomical Society, San Luis Obispo, CA 93403 

Abstract: Using a 22-inch Dobsonian reflector telescope and a Celestron Micro Guide eyepiece, 

four students from Arroyo Grande High School and Cuesta College, along with one 

members from the Central Coast Astronomical Society, made observations, and estimated 

the separation and position angle of the visual double star Nu Draco. The mean separation 

was found to be 62.0 arc seconds, while the mean position angle was found to be 139.5°. The 

results compared favorably with past observations. 

Introduction 

This research project was part of the Fall 2011 

Cuesta College Astronomy Research Seminar held at 

Arroyo Grande High School. Observations were conducted 

at Santa Margarita Lake on October 29, 2011 

(Besselian Epoch 2011.826), with a 22-inch Dobsonian 

telescope constructed by Reed and Chris 

Estrada. 

The objectives of this project were to: give new 

students the opportunity to collect data in the field 

with an experienced astronomer (Reed Estrada); allow 

students to experience the process of analyzing 

data as well as the drafting, completing, and reviewing 

a scientific paper; and contribute data on this 

double star to the growing number of reports. 

The binary star Nu Draco, 173215.88+551022.1 

per the Washington Double Star Catalog, was chosen 

for its relatively bright magnitudes (both are magnitude 

4.9) and its fairly wide separation of 63.4″ 

[Mason 2007]. 

The authors observed the binary star nu-1 and 

nu-2 in Draco, recording data during the observation, 

Figure 1: From left to right: Hollie Charles, Jordan Fluitt, 

Everett Heath, Grayson Ortiz, Russ Genet, and Reed Estrada. 

They pause before making their observations at Santa Margarita 

Lake’s Star Hill in Santa Margarita, California. 

and later analyzing the data to form a scientific paper. 

Except for Estrada and Genet, all of the authors 

were new to astronomical observations. 

Nu Draco is composed of nu-1, an A6 dwarf star, 

and nu-2, an A4 dwarf star. Nu Draco is also known

Vol. 8 No. 2 April 1, 2012 


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Table 1: Data observed and recorded for the binary star Nu Draco. 

Drift Time 

(seconds) 

Separation 

(arc seconds) 


(degrees) 

Mean 51.3 62 310.5 

Standard Deviation 0.6 3.0 2.9 

Standard Error 0.2 1.5 0.9 

# of Observations 10 4 10 

as a “metallic line” star due to its slow rotation rate. 

The period of rotation for the stars around one another 

is about 44,000 years [Kaler]. 

Equipment and Procedures 

A 22-inch Dobsonian mount (constructed by Reed 

and Chris Estrada and shown above in Figure 1) was 

equipped with a Celestron Micro Guide (see Figure 2 

below). 

The drift method was used to determine the scale 

constant in arc seconds per division using the liner 

scale in the Celestron Micro Guide eyepiece. The primary 

star nu-1, with nu-2 positioned below it, was 

placed on the linear scale and allowed to drift across 

the 60-division linear scale. After each measurement, 

the pair was repositioned by gently moving the telescope. 

Ten recordings of drift time were taken with no 

outliers. The drift time was measured with an iPhone 

-4 stopwatch with a resolution of 0.1 seconds. 

The position angles of the two stars were measured 

ten times on the 60 division scale. The eyepiece 

was rotated 180 degrees after each observation to reduce 

bias. The telescope was readjusted manually 

after each recording in order to reset the star’s position 

in the eyepiece. The separation of the stars was 

estimated by counting the number of graduations 

while holding the telescope steady and manually adjusting 

it to counteract the rotation of the Earth. We 

made these measurements four times. 

Observations and Results 

The values of the times it took the stars to drift 

across our eyepiece were consistent with no outliers, 

yielding an average of 51.33 seconds in 10 trials. We 

determined the scale constant to be 7.34 arc seconds 

per division using the formula: 

z = 

15.0411( t)cos( d) 

D 

where: z is the scale constant in arc seconds per division, 

15.0411 is the number of arc seconds per second 

of the Earth’s rotation, t is the average drift time, d is 

the declination of the star, and D is the number of 

divisions on the linear scale (60) 

The average position angle was found to be 139.5 

degrees, and the average separation was found to be 

62.0 arc seconds. The separation was found by multiplying 

each value we measured by our scale constant 

of 7.34 arc seconds per division. 

Figure 2: The illuminated reticle of the Celestron Micro 

Guide. 


During the class, the group made observations on 

the position angle and separation of the double star, 

Nu Draconis. Afterwards, the data were compiled into 

a scientific paper that described the equipment, observational 

methods, and processes that were used. 

Our observations compare favorably with those

Vol. 8 No. 2 April 1, 2012 


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reported by Haas [Haas 2006]. Where our separation 

was 62 arc seconds, hers was 63 arc seconds. Where 

our position angle was 310.5 degrees, hers was 311 

degrees. 

Our observations also compare favorably with the 

last (2010) observation of Nu Draco reported in the 

Washington Double Star Catalog [Mason 2010], 

which was made in 2010. The last observation measured 

311 arc seconds as their separation, while we 

measured 310.5. Where the last observation’s separation 

was 62, ours was also 62. 

All of our goals were met with this project. The 

students learned to make scientific observations 

alongside an experienced astronomer, they collected 

data and wrote a scientific paper, and they contributed 

data on the star. 




Observatory. We wish to thank external reviewers 

Joseph Carro, Sarah Collins, Thomas Frey and Vera 

Wallen for assisting us in the improving of our paper. 

References 

1. Haas, Sissy, 2006, Double Stars for Small Telescopes. 

Sky Publishing, Cambridge, MA. 

2. Kaler, Jim, (http://stars.astro.illinois.edu/sow/ 

kuma.html) 

3. Mason, Brian, 2010, The Washington Double Star 

Catalog. Astronometry Department, U.S. Naval 

Observatory.

Vol. 8 No. 2 April 1, 2012 


Page 160 

Three New Common Proper Motion Binaries in 

Cetus, Pisces and Leo Minor Constellations 

F. M. Rica 

Astronomical Society of Mérida, 

C/Toledo, no1 Bajo, 

Mérida E-06800, Spain 

Double Star Section of LIADA, 

Avda. Almirante Brown 5100 (Costanera), 

S3000ZAA Santa Fe, Argentina 

frica0@gmail.com 

Abstract: I present three new common proper motion binaries discovered during a project 

of measuring and study of neglected double stars. In addition to this, I present the study of 

two binaries also found by me but listed recently in the WDS catalog. Forty-four measures 

of position angles and angular distances were performed using public photographic and 

digital online surveys and catalogs with epoch between 1953 and 2011. The astronomical 

literature was consulted and my astrophysical characterization was determined by parameters 

such as spectral types, absolute magnitudes, distances, stellar masses, tangential velocities, 

reddening, etc. A dynamical study allowed me to classify these pairs of stars according 

to their nature. Four of them were classified as candidate common origin binaries and 

one as a candidate to be a binary with stellar components gravitationally bound 

1. Introduction 

A year ago, LIADA Double Star Section started a 

project called MIEDA, Medición y Estudio de Estrellas 

Dobles Abandonadas (Measuring and Study of 

Neglected Double Stars). In a first phase of this project 

we used the ALADIN tool (Bonnarel et al. 2000) 

using a designed script, to identify neglected double 

stars. In this phase I found 5 uncataloged common 

proper motion pairs, although two of them were recently 

listed in WDS during the edition of this work. 

In this work I performed relative (θ and ρ) astrometric 

measures using photographic and digital 

online surveys in addition to astrometric catalogs 

(2MASS). A search for photometric and kinematical 

information was done in the astronomical literature. 

Finally astrophysical characterizations of the stellar 

components and a dynamic study of the double stars 

were performed. 

The organization of this paper is as follows. In 

Section 2, I present the astrometric measures. In 

Section 3, I detail the astrophysical study. In Section 

4, I discuss the study of the nature of these pairs. 

Section 5, includes detailed comments about the 

studied binaries. Finally in Section 6, I present my 

conclusions. 

2. Measures of Position Angles and Angular 

Distances 

In this work I use photographic plates from Digitized 

Sky Survey (hereafter DSS), and digital surveys 

such as DENIS (Deep Near Infrared Survey of

Vol. 8 No. 2 April 1, 2012 


Page 161 

Three New Common Proper Motion Binaries in Cetus, Pisces and Leo Minor Constellations 

the Southern Sky) in I, J, and K bands and SDSS 

(Sloan Digital Sky Survey) in ugriz bands. In addition 

to this, the astrometry of 2MASS catalog was 

used to obtain θ and ρ measures. 

Antonio Agudo Azcona (AAA) performed an astrometric 

measure of FMR 27 in 2011 using a Schmidt- 

Cassegrain of 20 cm of diameter. The image was 

taken using a CCD Atik 16IC-S monochrome and a 

reduced focal Hirsch SCT f/6.3. This configuration 

gave a focal length of 1384 mm, a scale of 1.24 arcsec 

and a field of view of 16.1' x 12.0'. 

Ramón Palomeque Messía (RPM) also performed 

an astrometric measure of FMR 27 using a Schmidt- 

Cassegrain of 20 cm of diameter. The image was 

taken using a Orion SSDS-II Color camera. He took 

500 images of 1 second exposure time and later 

stacked 100 images using Maxim. Reduc was used for 

the astrometric measure. 

Table 1 lists Forty-four position angles (θ) and 

angular distances (ρ) measures with observational 

epochs between 1953 and 2011. This table gives the 

WDS name (or the proposed name for those binaries 

not listed in WDS) in column (1), the Besselian observational 

epoch, the position angle and angular distances 

in columns (2)-(4); the aperture of the telescope 

(in inches) in column (5) and finally, in the last column 

the method used to obtain the relative astrometry: 

• DSS: photographic plates from Digitized Sky 

Survey 

• DENIS-band: digital images from DENIS. 

“band” is the photometric band used in the 

image (I, J, and K). 

• SDSS-band: digital images from SDSS. 

“band” is the photometric band used in the 

image . 

• 2MASS: astrometry from 2MASS catalog 

3. The Astrophysical Study 

A detailed astrophysical study of the new stellar 

systems and for the stellar components was performed 

(see Table 2). The guidelines of the astrophysical 

study were published in Benavides et al. (2010) in 

sections 3 to 10. The astrophysical data were corrected 

for interstellar reddening. The reddening was 

nearly negligible except for LEP 121 which E(B-V) = 

0.09. In the followed subsections I add new points to 

the astrophysical guidelines. 

3.1 Photometry 

Photometric information was obtained from the 

following catalogs: 

• the infrared J, H, and K photometry from 2MASS 

(Hog et al. 2000) catalog, 

• the V magnitude was determined using the red magnitudes 

from CMC14 (CMC 2006) and UCAC3 

(Zacharias et al. 2009). For more detail, see the work 

published by Rica (2011a). 

• I consulted the SDSS (Adelman-McCarthy J.K. et al. 

2009) catalog. The ugriz photometry was converted 

to V, U-B, B-V, V-I Johnson photometry. For more 

detail about this transformation see the work published 

by Rica (2011a). Where SDSS photometry is 

available , we use the V magnitude determined if the 

star is weaker that 15 magnitude in g band. 

4. Are These Double Stars Gravitationally 

Bound 

In Benavides et al. (2010), in section 9, and in 

Rica (2011b) I described in detail the criteria used to 

determine the nature of the pairs. The relative motions 

of the systems were calculated plotting rectangular 

coordinates x = ρ * sin θ and y = ρ * cos θ (prior 

to correction of θ for precession and proper motion) 

against time (read the Appendix in Rica (2011b)). The 

scope of the weighted linear fit (calculated using 

Mathematica 5.0) gave the value of the relative 

proper motion in arcsec*yr -1 . The initial weights for 

measures were assigned using a data weighting 

scheme published in Rica (2010). 

If the distance is known then I can convert the 

relative motion in relative velocity (in km s -1 or in AU 

yr -1 ), a key datum to determine if Keplerian motion is 

possible in these stellar systems. Often the uncertainties 

in the observational data don’t allow the determination 

with certainty the nature of the pair. In that 

case, I determined the probability that a double star 

is gravitationally bound. 

For this, I use celestial mechanics to determine if 

the relative projected velocity of B with respect to A is 

smaller than the maximum orbital velocity or the escape 

velocity. I analyzed the probability that a binary 

is a gravitationally bound system using a Monte 

Carlo simulation with 25,000 iterations. Monte Carlo 

methods are a class of computational procedures that 

rely on repeated random sampling to compute their 

results. For more detail, see section 5.2 of the work of 

Rica (2011b). 


Vol. 8 No. 2 April 1, 2012 


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Table 1: Astrometric measures. 

Double Epoch θ (deg) ρ (as) Aperture Observer Method 

FMR 26 1954.675 205.77 20.19 48 FMR DSS 

1954.675 205.48 20.79 48 FMR DSS 

1977.637 204.69 20.29 48 FMR DSS 

1981.767 205.61 20.05 48 FMR DSS 

1982.633 205.40 20.37 48 FMR DSS 

1995.826 204.83 20.08 48 FMR DSS 

1996.866 205.07 20.39 48 FMR DSS 

1997.808 205.31 20.18 48 FMR DSS 

1998.626 205.50 20.23 51 FMR 2MASS 

1999.595 205.65 20.34 39 FMR DENIS-I 

1999.595 205.81 20.13 39 FMR DENIS-J 

FMR 27 1953.779 171.65 363.056 48 FMR DSS 

1953.779 171.58 362.785 48 FMR DSS 

1983.682 171.56 362.525 48 FMR DSS 

1990.810 171.54 363.164 48 FMR DSS 

1993.622 171.52 363.224 48 FMR DSS 

1995.801 171.57 363.220 48 FMR DSS 

1997.828 171.54 362.94 51 FMR 2MASS 

2011.907 171.50 362.85 8 AAA CCD 

2011.983 171.49 362.69 8 RPM CCD 

LEP 122 1958.524 200.6 7.3 48 FMR DSS 

1974.61 200.5 7.35 48 FMR DSS 

1979.629 194.0 6.98 48 FMR DSS 

1980.559 190.3 7.23 48 FMR DSS 

1987.378 199.5 7.15 48 FMR DSS 

1992.41 202.9 6.48 48 FMR DSS 

1996.699 199.9 6.64 48 FMR DSS 

1998.53 199.8 7.22 39 FMR DENIS-K 

1998.53 200.5 7.17 39 FMR DENIS-I 

1998.53 199.4 7.09 39 FMR DENIS-J 

1999.507 200.6 7.21 51 FMR 2MASS 

LEP 121 1976.483 134.2 3.53 48 FMR DSS 

1996.545 134.0 4.70 48 FMR DSS 

1998.414 130.7 4.09 51 FMR 2MASS 

FMR 28 1955.29 138.49 18.56 48 FMR DSS 

1983.849 139.14 18.43 48 FMR DSS 

1989.928 139.01 18.81 48 FMR DSS 

1993.197 138.82 18.68 48 FMR DSS 

1998.217 139.00 18.70 51 FMR 2MASS 

1999.96 138.79 18.73 48 FMR DSS 

2004.083 138.90 18.70 98 FMR SDSS-g 

2004.083 138.91 18.58 98 FMR SDSS-g 

2004.083 139.05 18.63 98 FMR SDSS-g 

2004.083 138.75 18.64 98 FMR SDSS-g

Vol. 8 No. 2 April 1, 2012 


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FMR 26 FMR 27 LEP 122 LEP 121 FMR 28 

A B A B A B A B A B 

RA2000 01h 06m 20.62s 01 h 07 m 27.07 s 18h 29m 16.90s 17 h 08 m 25.59 s 10 h 00 m 19.13 s 

DEC 2000 -22º 24’ 45.0” +24º 53’ 41.8” -30º 59’ 48.9” -22º 09’ 24.0” +31º 19’ 42.2” 

V 16.53 a) 19.2 b) 12.72 a) 15.42 a) 13.87 a) 14.65 a) 16.5 g) 17.5 g) 15.63 f) 18.93 f) 

B – V --- --- --- --- --- --- --- --- --- --- 

V – I --- --- --- --- --- --- --- --- --- --- 

K c) 12.38 13.45 10.65 12.11 9.49 9.94 12.21 12.79 13.21 15.18 

J – H c) +0.60 +0.55 +0.42 +0.61 +0.48 

+0.51 

0.51 

+0.47 +0.48 +0.57 +0.51 

H – K c) +0.22 +0.28 +0.07 +0.16 +0.28 +0.22 +0.24 +0.25 +0.15 +0.23 

J – K c) +0.82 +0.83 +0.50 +0.77 +0.76 +0.73 +0.71 +0.73 +0.72 +0.74 

V-K +4.15 +5.80 +2.07 +3.31 +4.38 +4.71 +4.3 +4.7 +3.14 +4.49 

-36.4 -30.7 +130 +138 

μ(α) [mas/yr] 

± 4 d) ± 4 d) ± 2 d) ± 4 d) +457 d) -29.5 -28.5 

+460 +368 +361 

± 4.2 d) ± 4.3 d) 

μ(δ) [mas/yr] 

Table 2: Astrophysical data for the stellar component of the binaries. 

-99.0 -98.5 -4 -5 

± 4 d) ± 4 d) ± 2 d) ± 4 d) -158 d) -155 +366 +367 

-56.3 

±4. 2 

d) 

-62.4 

± 4.3 d) 

Spectral Type e) M2V M4.5V G9V K7V M2.5V M3V M3VI M5VI K6V M2.5V 

Distance [pc] e) 192 118 212 228 43 41 108 113 385 383 

Mv e) 10.06 13.80 5.95 8.46 10.64 11.53 11.04 11.96 7.64 10.95 

BC e) -1.76 -2.46 -0.22 -0.65 -1.90 -2.03 -2.1 -2.5 -0.57 -1.90 

Mass e) 0.37 0.18 0.84 0.66 0.37 0.26 --- --- 0.70 0.37 

Vtan [km s -1 ] e) 96 58 130 149 99 94 250 275 116 125 

E(B-V) 0.01 0.01 0.04 0.05 0.02 0.02 0.09 0.09 0.02 0.02 

Notes: 

a) Determined using UCAC3 (Zacharias el at. 2010) and 2MASS (Cutri 2000) photometry 

b) Determined using USNO-B1.0 (Monet et al. 2003) photometry 

c) 2MASS catalog 

d) catalog PPMXL (Roeeser, Demleitner, & Schilbach 2010) 

e) this work 

f) SDSS catalog 

g) WDS catalog;

Vol. 8 No. 2 April 1, 2012 


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5. Notes on Stellar System 

FMR 26 

This is a very faint (16.53 and 19.2 magnitudes) 

binary located in the constellation Cetus (Figure 1). It 

is composed of M2V and M4.5V stars separated by 

about 20.2” with a common proper motion of -31 mas 

yr -1 in AR and -99 mas yr -1 in DEC. The secondary 

has a V magnitude of 19.2, determined using the 

USNO-B1.0 photometry. But, if we use the GSC2.3 

photometry, a V magnitude of 18.2 and a M3V spectral 

type is obtained for the secondary component. 

The V magnitudes determined using a photographic 

catalog such as USNO-B1.0 and GSC2.3, have an uncertainty 

of about 0.3-0.4 magnitudes. To this value 

we have to add the systematic errors usually found in 

the photographic plates. I decided to use the V magnitude 

from USNO-B1.0 because the VJHK photometries 

are a better fit to the spectral types – photometry 

relations. These sources of error make our 

astrophysical data have larger errors than in other 

studies. 

The Monte Carlo simulation indicates a common 

distance probability of about 60 % (146.5 ± 18.1 pc) 

and a probability of binarity (stellar components 

gravitationally bound) of less than 1%. The significant 

probability of common distance and the common 

proper motion of about 105 mas yr -1 ( relative motion 

Δμ = 5.07 ± 4.89 mas yr -1 ) for the components, suggest 

a binary nature of common origin (no orbiting stars). 

FMR 27 

This high common proper motion pair, located in 

the Pisces, is composed by stars of 12.72 and 15.42 

magnitudes with spectral types G9V and K7V (Figure 

2). It is a very wide pair of stars separated by about 

363”. The relative astrometric measures and the high 

relative motion calculated (12.6 ± 8.6 mas yr -1 ) suggest 

that this pair of stars could be not gravitationally 

bound (although the level of uncertainty don’t allow 

us conclude this with security). If the UCAC3 proper 

motion is used, then the relative motion is reduced to 

2.8 mas yr -1 . Even using this small relative motion, 

the criteria used conclude that the stellar components 

of FMR 27 are not gravitationally bound. So this pair 

of stars is likely a binary of common origin. 

LEP 122 (WDS 18293-3100) 

This is a very high common proper motion binary 

(μ = 0.483 arcsec yr -1 ) discovered by Lepine (2008) in 

Figure 1: RGB image of the binary star FMR 26 where the apparent 

motion is clearly visible. 

Figure 2: RGB image of the extremely wide binary star FMR 27 

where the apparent motion is clearly visible

Vol. 8 No. 2 April 1, 2012 


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the constellation Sagittarius. WDS catalog lists spectral 

types K+K (Figure 3). In this work I determined 

that this system is located 41 - 43 pc from us and is 

composed of 13.87 and 14.65 magnitude stars of spectral 

types of M2.5V and M3V. It is a close pair (about 

7”) with a poorly determined relative motion of 4.7 ± 

6.2 mas yr -1 . The 25,000 Monte Carlo simulations that 

I ran showed that in 77 % of the simulations, the observed 

projected velocity was smaller than the maximum 

escape velocity. So this pair of stars is likely a 

binary with gravitationally bound stellar components. 

The projected distance calculated is 303 AU and using 

Kepler’s Third Law (assuming circular and face-on 

orbit) a period of 9,400 years is obtained. A common 

origin nature cannot be ruled out. 

Our measures, using 2MASS catalog and DENIS 

images, seem to be the same as those of Skiff (2011) 

listed in WDS catalog. 

LEP 121 (WDS 17084-2209) 

This is a very high common proper motion binary 

(0.488 arcsec yr -1 ) discovered by Lepine (2008) in the 

constellation Leo (Figure 4). The WDS catalog lists 

spectral types K+K. In this work, I determined that 

this system is located at 108 - 113 pc and is composed 

of two subdwarf candidate stars of M3VI and M5VI 

spectral types with magnitudes 16.5 and 17.5 (WDS). 

I determined the subdwarf nature using reduced 

proper motion diagrams. LEP 121 is a close pair separated 

by 4.1” with a poorly determined relative motion 

of 16 mas yr -1 . This relative motion was calculated 

from the proper motion of the stellar components. 

Astronomical literature does not list proper 

motion data, so the proper motions listed in this work 

have been calculated from two photographic plates 

taken on 1976.483 and 1996.545. The projected distance 

is 453 AU. I calculated a very similar photometric 

distance for the primary (108 pc) and the secondary 

(113 pc) components. This common distance, in 

addition to the common proper motion, indicates that 

LEP 121 is a binary star. But the large relative motion 

suggests that it is a common origin binary with 

stellar component not gravitationally bound. 

Our measure with epoch 1998.414 was obtained 

using 2MASS catalog. WDS lists a measure from 

Skiff (2011) that seems to be also obtained using the 

2MASS catalog or image. 

FMR 28 

This is a distant and faint common proper motion 

(0.064 arcsec yr -1 ) binary located in the constellation 

Leo Minor at about 384 pc (Figure 5). It is composed 

of two dwarf stars of K6V and M2.5V spectral types 

Figure 3: RGB image of the binary star LEP 122 where the 

apparent motion is clearly visible 

Figure 4: RGB image of the binary star LEP 121.

Vol. 8 No. 2 April 1, 2012 


Page 166 


with magnitudes 15.63 and 18.93. It is separated by 

18.6 - 18.7” with a relative motion of 2.26 ± 3.40 mas 

yr -1 . The projected distance is 7,181 AU. I calculated 

a very similar photometric distance for the primary 

(385 pc) and the secondary (383 pc) component. This 

common distance, in addition to the common proper 

motion indicates that FMR 28 is surely a binary star. 

The 25,000 Monte Carlo simulations that I ran 

showed that only in the 5-6% of simulations the observed 

projected velocity was less than the maximum 

escape velocity. So FMR 28 is likely a common origin 

binary star. 

Conclusions 

During the course of the MIEDA project I found 5 

uncataloged wide common proper motion pairs. During 

the completion of this study two of them were recently 

included to WDS catalog, so in this work I present 

three new common proper motion binaries (FMR 

26, FMR 27 and FMR 28). Astrophysical characterizations 

and astrometric measurements were performed. 

In spite of the low quantity of the astrometric measures 

and the small time baseline (less than 50 years), 

I performed a dynamical study to determine the probability 

to be pairs with stellar components gravitationally 

bound. All five pairs have stellar components 

with a significant possibility to be the same distance 

from us and with common proper motion. But only 

one pair (LEP 122) has the likely probability to be 

gravitationally bound. LEP 122 is a pair of red dwarf 

stars (M2.5V and M3V) separated by 303 AU and located 

at a distance of about 42 pc. Its orbital period is 

estimated to be about 9,400 years. The other pairs are 

surely binary stars of common origin, that is, with 

stellar components that don’t orbit each other. 


This project made use of data products from the 

Two Micron All Sky Survey, which is a joint project of 

the University of Massachusetts and the Infrared 

Processing and Analysis Center/California Institute of 

Technology, funded by the National Aeronautics and 

Space Administration and the National Science Foundation. 

DENIS is the result of a joint effort involving human 

and financial contributions of several Institutes 

mostly located in Europe. It has been supported financially 

mainly by the French Institut National des 

Sciences de l'Univers, CNRS, and French Education 

Ministry, the European Southern Observatory, the 

State of Baden-Wuerttemberg, and the European 

Commission under networks of the SCIENCE and 

Figure 5: Photographic plate where FMR 28 appears at the 

center of the image. 

Human Capital and Mobility programs, the Landessternwarte, 

Heidelberg and Institut d'Astrophysique 

de Paris. 

The Digitized Sky Surveys were produced at the 

Space Telescope Science Institute under U.S. Government 

grant NAG W-2166. The images of these surveys 

are based on photographic data obtained using 

the Oschin Schmidt Telescope on Palomar Mountain 

and the UK Schmidt Telescope. The plates were processed 

into the present compressed digital form with 

the permission of these institutions. 

This research made use of the Washington Double 

Star Catalog maintained at the U.S. Naval Observatory. 

We kindly acknowledge Frank Smith for the English 

Grammar. 

References 

Adelman-McCarthy J. K. et al., 2009, ApJS, 182, 543 

Benavides R., Rica F., Reina E., Castellano J., Naves 

R., Lahuerta L., Lahuerta S., 2010, JDSO, 6, 30 

Bonnarel F. et al., 2000, A&AS, 143, 33 

CMC, 2006, Copenhagen University Obs., Institute of 

Astronomy, Cambridge, Real Instituto y Observatorio 

de la Armada en San Fernando 

Cutri R. N. et al. Explanatory to the 2MASS Second 

Incremental Data Release, 2000, http:// 

www.ipac.caltech.edu/2mass/releases/second/ 

index.html

Vol. 8 No. 2 April 1, 2012 


Page 167 


Høg E. et al., 2000, A&A, 355, 27 

Lepine S., 2008, AJ, 135, 2177 

Monet D. G. et al., 2003, AJ, 125, 984 

Rica F. M., 2010, RMxAA, 46, 263 

Rica F. M., 2011a, JDSO, 7, 114 

Rica F. M., 2011b, JDSO, 7, 254 

Roeeser S., Demleitner M., Schilbach E., 2010, AJ, 

139, 2440 

Skiff B. A., 2011, private communication 

Zacharias N. et al., 2009, VizieR Online Data Catalog, 

1/315, http://vizier.ustrasbg. fr/viz-bin/VizieR- 

source=I/315 

Zacharias N. et al., 2010, AJ, 139, 2184

Vol. 8 No. 2 April 1, 2012 


Page 168 

Study of a New CPM Pair 

2Mass 01300483-2705191 

Israel Tejera Falcón 

Observatorio Vecindario 

Canary islands, Spain) 

TWILIGHTALLEHOUSE@hotmail.es 

Abstract: In this paper I present the results of a study of 2MASS 01300583-2705191 as 

components of a common proper motion pair. I used the PPMXL catalog’s proper motion 

data to select this system, which has a high declination proper motion but low aright ascension 

proper motion with large errors in this case. I also determined the proper motions independently, 

obtaining similar proper motions for both components, however I used the 

PPMXL values in this study. On the other hand, with the absolute visual magnitude of 

both components, I obtained distance moduli 7.95 and 7.92 Which put the components of 

the system at a distance of 389.0 and 383.7 parsecs. Taking into account errors in determining 

the magnitudes, this means that the probability that both components are situated at 

the same distance is near 100%. I suggest that this pair be included in the WDS catalog 

Introduction 

The main purpose is to determine some important 

astrophysical features of 2Mass J01300483- 

2705191 (Figure 1), such as distance, spectral type of 

the components, etc. It was achieved by an astrophysical 

evaluation using kinematic, photometric 

spectral and astrometrical data, obtaining enough 

information to determine if there is a gravitational 

tie between both components and its nature. In this 

study I used Francisco Rica Romero’s spreadsheets 

[1] that makes many astrophysics calculation. 

Methodology 

Proper motion / kinematics 

I obtained the proper motions for the pair from 

the PPMXL catalog (a catalog that provides positions 

and proper motions), which are shown in Table 1. I 

also calculated the resulting tangential velocity 

(Table 2). 

Figure 1: Picture based on POSS plate that shows the system 

under study. Inset identifies the components.

Vol. 8 No. 2 April 1, 2012 


Page 169 


Table 1: Proper motion of the pair described in 

this study 

Component Proper Motion RA Proper Motion DEC 

A -2.1 ± 4.0 -31.6 ± 4.0 

B -0.5 ± 4.0 -28.6 ± 4.0 

Table 5:Theta / Rho measurements obtained with 

Reduc Software 

Besselian Date Theta (deg) Rho (as) 

1955.9391 216.51 8.65 

1986.5699 211.34 8.368 

1996.6125 212.05 8.32 

1997.6793 213.14 8.484 

Table 2: Tangential velocity calculation 

based on PPMXL proper motions 

Tangential Velocity 

Calculation 

Mu (alpha) = -0.002 -0.016 

Mu (delta) = -0.032 -0.029 

Pi (“) = 0.0026 0.0026 

Ta (km/s) -4 -29 

Td (km/s) -58 -52 

Vt (Km/s) 58 59 

I made an independent study of the proper motions 

of this system, where I calculated component’s 

positions from differently dated plates that I obtained 

using Aladin Sky Atlas with a timeline difference of 

41.7402 years. I made the measurements using Astrometrica 

software, the stars were not saturated at 

any plate, obtaining easy measurements. These results 

are shown in Tables 3 and 4. That study revealed 

that the proper motions are similar and suggest 

that this system could be a CPM pair. These 

results are the reason I decided to study this system. 

Relative Astrometry 

Relative astrometry measurements were based on 

A 

B 

Table 6: Photometric magnitudes pulled from 2MASS 

(infrared) and USNO B1.0 catalogs 

J H K B2 R2 

A 13.55 12.933 

12.69 

2 

18.53 15.56 

B 14.838 14.275 

13.91 

9 

20.11 17.07 

plates with different dates obtained from Aladin software 

and with resolution 1.1”. I used Astrometrica 

software to obtain angle deviation and applied that 

value on Reduc software calibration parameters for 

each plate. I also obtained position angle (theta) and 

separation (rho) values for each plate using Reduc 

(see Table 5) . 

Photometry / Spectral Type of the Components 

I retrieved all plates with plate resolution around 

1 arcsecond/pixel and catalog data of the image field 

from USNO B1.0 and 2MASS (Table 6). 

Using Francisco Rica Romero’s astrophysics 

spreadsheet “SDSS-2MASS-Johnson conversions” [1], 

I obtained the results shown in Table 7. 

With this set of photometry in bands J,H,K, the 

deduced B,V,I and using the Rica Romero’s 

“Astrophysics” spreadsheet, I determined the spectral 

Table 4: Proper motions deduced using coordinates from Besselian date plates (Besselian date vs 

coordinates) not used in this study. 

Besselian Date Primary RA(º) Primary DEC(º) Secondary RA(º) Secondary DEC(º) 

1955.9391 22.515500 -27.087861 22.514000 -27.089889 

1986.5699 22.515458 -27.088167 22.514000 -27.090083 

1996.6125 22.515375 -27.088306 22.513917 -27.090256 

1997.6793 22.515292 -27.088194 22.513708 -27.090139

Vol. 8 No. 2 April 1, 2012 


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Table 7: Based at JHK (2MASS) and B2, R2 (USNO B.1) 

photometric magnitudes and using Francisco Rica Romero’s 

“SDSS-2MASS-Johnson conversions” I obtained 

color index (B-V), (V-I), Magnitude V and later with 

“Astrophysics” spreadsheet, Bolometric correction. 

Color B-V 

Color V-I Magnitude V Bolometric 

correction 

A 1.30 1.38 15.93 -0.752 

B 1.35 1.48 17.39 -0.865 

Table 8: Reduced Proper Motion 

BAND Mag (A) H(A) Mag (B) H(B) 

V 15.93 13.4 17.39 15.0 

K 10.2 10.5 13.919 11.5 

Figure 2: Reduced-Proper diagrams after Luyten’s White 

Dwarf Catalog [4]. This diagram shows that both components 

are situated in the swarf/subdwarf region. 

Table 9: Distance moduli and distances in parsecs, 

values obtained using Francisco Rica Romero’s 

spreadsheet “Astrophysics” 

Component 

Distance 

modulus 

Distance 

parsec 

A 7.95 389.0 

B 7.92 383.7 

type of each component from photometric data and 

obtained K7V and K9V for the primary and secondary, 

respectively. 

Using the same spreadsheet, I obtained the reduced 

proper motions for the companions presented in 

Table 8. The Reduced Proper Motion Diagram (Figure 

2) shows that both components are situated in the 

dwarf/subdwarf region. This suggests that the primary 

component and its companion are main sequence 

stars. 

The absolute visual magnitude of both components 

enabled the calculation the distance moduli. 

Again, I used Rica Romero’s spreadsheet 

“Astrophysics”, the results are shown in Table 9. 

The distance moduli obtained for each component 

were similar. Taking into account the errors in determining 

the magnitudes, I conclude that the probability 

that components are at the same distance is almost 

100% 

Conclusions 

Using the spectroscopy obtained above, I estimate 

the sum of the masses to be 1.15 solar masses. Using 

the above calculated distances, the Wilson and Close 

criteria [2,3] indicate a physical system. 

The distance moduli calculated above, put both 

components at the same distance 389.0 (primary) and 

383.7 (secondary) parsecs Which means that the 

probability that both components are at the same distance 

is almost 100%, which is a good indicator about 

the possible physical relation between the stars. 

With respect to kinematics, the RA proper motion 

of this system is low (as indicated by PPMXL), for this 

reason, I verified the kinematics through digitized 

plates from different dates, the difference being 

41.7402 years, and obtained similar results on RA 

proper motions and nearly the same values for DEC. 

The latest image available from Aladin software 

(1997.6793) gives astrometry values: θ = 213.14º and 

ρ = 8.484”. According to these data and using Rica 

Romero’s spreadsheet, I estimate the parameter (p/µ) 

representing the time it takes the star to travel a distance 

equal to their angular separation with its motion 

µ at T = 266 years. This also indicates that the 

stars are likely to be physically associated. 

In summary, with the present information I think 

that this pair should be considered a binary and I 

suggest that this pair be included in the WDS catalog.

Vol. 8 No. 2 April 1, 2012 


Page 171 



I used Florent Losse’s “Reduc” software for relative 

astrometry and Herbert Raab’s “Astrometrica” 

software to calculate plate’s angle deviation. 

I used Francisco Rica Romero’s “Astrophysics” 

and “SDSS-2MASS-Johnson conversions” with many 

useful formulas and astrophysical concepts. 

The data analysis for this paper made use of the 

Vizier astronomical catalogs service maintained and 

operated by the Center de Donnès Astronomiques de 

Strasbourg (http://cdsweb.ustrasbg.fr) 

References 

1. Francisco Rica Romero, private communication, 

2011. 

2. Reid, Neid, et al., AJ, 121, 489, 2001. 

3. Close, S.M., et al., ApJ, 587, 407-422, 2003. 

4. Jones, E. M., AJ, 177, 245, 1972.

Vol. 8 No. 2 April 1, 2012 


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April 1, 2012 

Volume 8, Number 2 

Editors 

R. Kent Clark 

Rod Mollise 

Editorial Board 

Justin Sanders 

Michael Boleman 

Advisory Editor 

Brian D. Mason 

The Journal of Double Star Observations is 

an electronic journal published quarterly by 

the University of South Alabama. Copies can 

be freely downloaded from 

http://www.jdso.org. 

No part of this issue may be sold or used in 

commercial products without written permission 

of the University of South Alabama. 

©2012 University of South Alabama 

Questions, comments, or submissions may be 

directed to rclark@jaguar1.usouthal.edu 

or to rmollise@bellsouth.net 

The Journal of Double Star Observations (JDSO) 

publishes articles on any and all aspects of astronomy involving 

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interested in observations made by amateur astronomers. 

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or conclusions about double or binary stars may undergo 

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by an amateur astronomer will be reviewed by other amateur 

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