OF THE ROGER N. CLARK

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VISUAL ASTRONOMY OF THE DEEP SKY A VISUAL ATLAS OF DEEP-SKY OBJECTS -- • • • • • • • • • . . • • • • e. • o • • • • • -- 10' -- • South is to the left. Photograph oJ M45. (Courtesy Mount Wilson and Las Campanas Observatories, Carnegie Institution oJ Washington.) Scale: 4.4 arc-min/cm 8·inch f/ 11.5 Cassegrain 28mm Kellner (82X) 20mm ErfIe (117X, best for nebula) Drawing oJ M45 Viewing Distance (cm) 25X :31 50 X: 16 100x: 8 200 X :4 300 X :2.6 400x:2 air mass: 1.05, faintest star: 14.2 at zenith, 188X, no tracking 10/08/83 1 1:40--12: 15 UT at Waianae ranch, Hawaii; R. Clark 92 93
-- Brightest stars of the Pleiades VISUAL ASTRONOMY OF THE DEEP SKY Star Name Magnitude Star Name Magnitude 25 Tauri Alcyone 2.87 19 Tauri Taygeta 4.29 (Eta) 28 Pleione 5.09 27 Atlas 3.62 16 Celaeno 5.44 17 Electra 3.70 21 Asterope 5.64 20 Maia 3.86 18 5.65 23 Merope 4.17 22 6.41 observation proved different, however, because the nebula could be seen well at as high as 82 X. And when the magnification was increased tD 117 X, the nebula became easier! Under excellent conditions, the Merope Nebula is easily seen in the 3-inch finder at 31X. The Pleiades' many and varied stars and delicate nebulosity provide a beautiful view to the amateur. It is no wonder the cluster is called the most studied and photographed of astronomical objects. 6.2 · 7.7 · Pleiades 6.8 . 7.0 · Pleione • Alcyone Atlas . (2.9) (5.1) • (3.6) .6.2 6.6 · 6.S- 7.3- 7.0 · Asterope • (5.3) • 7.4 · Maia. (3.9) • Merope (4.2) • Taygeta Figure 7.1. The brightest Pleiades, with visual magnitudes. To the naked Asterope appears single; the magnitude is combined light of both stars. 6.2-magnitude star at upper left is also naked-eye blend. From Sky & November, 1985. (4.3) M l (NGC 1952), THE CRAB NEBULA: SUPERNOVA REMNANT IN TAURUS RA. 05h 34.5m, Dec. 220 01' (2000.0) Technical. Messier I has been known as the A VISUAL ATLAS OF DEEP-SKY OBJECTS Crab Nebula ever since the third Earl of Rosobserved it with his 36-inch telescope in 44. In _the drawing he made, the nebula's filaments suggest the legs of a crab. Photoments throughout a diffuse green oval. and certainly the youngest Messier object. It is the expanding remnant of a brilliant naked-eye supernova that was seen in July, 1054. Now 5 by 3 arc-minutes in size, Ml is raphs show a beautiful network of red fila M1 is one of the youngest objects in the sky growing by nearly a half arc-minute per century. Changes have been photographed in only a couple of decades. Ml is about 6000 light-years distant and 6 light-years across. It is one of the strongest radio sources in the sky and also emits strong X-rays. Near the center of the nebula is a 16th-magnitude star that flashes 30 times a second in visible light, radio, and X-rays. This is a pulsar, the superdense neutron-star core of an old supernova. It is thought to be only 20 kilometers in diameter, and so dense that a teaspoonful of its matter would have a mass of several million tons! The flash rate corresponds to its period of rotation. Its very strong magnetic field spins with the star 30 times a second; energetic electrons trapped in the field produce the radiation. The pulsar is actually pumping energy into the nebula, so the expansion rate is increasing. Visual. M I can be seen in binoculars and small telescopes as a small, faint patch. With a visual magnitude of 9 and a size of about 5 by 3 arc-minutes, it has a mean surface brightness of20.6 magnitudes per square arcsecond. Large amateur telescopes under dark skies will show some of the filaments, though they are often difficult. At low powers (60X or less) few details are visible. At higher powers the nebula's outline begins to depart from a smooth oval. In the 8-inch at 188X, the "bay" to the east is visible, and the whole thing takes on the appearance of two oblong nebulae side by side. No stars could be seen inside the nebula with the 8-inch, but many were around it. 94 95
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OF THE ROGER N. CLARK
Page 3 and 4: Published by Sky Publishing Corpora
Page 5 and 6: CONTENTS M78 (NGC 2068) NGC 207 1,
Page 7 and 8: PREFACE During research for this bo
Page 9 and 10: VISUAL ASTRONOMY OF THE DEEP SKY AB
Page 11 and 12: VISUAL ASTRONOMY OF THE DEEP SKY TH
Page 13 and 14: .. .. .. .. VISUAL ASTRONOMY OF THE
Page 17 and 18: e viewed with enough magnification
Page 21 and 22: lens and a piano-convex eye lens. A
Page 25 and 26: controlled depends on how many laye
Page 27 and 28: The Lumicon H-Beta Filter (Figure 3
Page 29 and 30: every 1 ° in declination and 4 min
Page 31 and 32: error of only one quarter the field
Page 33 and 34: Table 4.1. Ideal limiting magnitude
Page 35 and 36: 5 Making drawings and keeping recor
Page 37 and 38: more detail in the future. They add
Page 39 and 40: .. .. .. ... Contrast (C) C Log(C)
Page 41 and 42: VISUAL ASTRONOMY OF THE DEEP SKY A
Page 47 and 48: --- VISUAL ASTRONOMY OF THE DEEP SK
Page 49 and 50: --- M76 (NGC 650-651), PLANETARY NE
Page 53: -- -- M45, THE PLEIADES OPEN CLUSTE
Page 57 and 58: M42 (NGC 1976), M43 (NGC 1982), THE
Page 59 and 60: --- --- --- VISUAL ASTRONOMY OF THE
Page 61 and 62: -- --- NGC 2023 NGC 2024, IC 434 (T
Page 63 and 64: --- --- M78 (NGC 2068), NGC 2071, D
Page 65 and 66: VISUAL ASTRONOMY OF THE DEEP SKY --
Page 67 and 68: --- M67 (NGC 2682), OPEN CLUSTER IN
Page 69 and 70: -- VISUAL ASTRONOMY OF THE DEEP SKY
Page 71 and 72: --- -- M82 (NGC 3034), PECULIAR GAL
Page 73 and 74: -- --- --- MI05 (NGe 3379) NGe 3384
Page 77 and 78: MI09 (NGe 3992), GALAXY IN URSA MAJ
Page 79 and 80: -- --- M99 (NGC 4254), GALAXY IN CO
Page 81 and 82: == -- VISUAL ASTRONOMY OF THE DEEP
Page 83 and 84: --- --- -- NGC 4449, GALAXY IN CANE
Page 85 and 86: -- -- --- VISUAL ASTRONOMY OF THE D
Page 87 and 88: --- -- M90 (NGC 4569), GALAXY IN VI
Page 89 and 90: --- -- M94 (NGC 4736), GALAXY IN CA
Page 93 and 94: -- VISUAL ASTRON0MY OF THE DEEP SKY
Page 95 and 96: -- --- -- VISUAL ASTRONOMY OF THE D
Page 97 and 98: -- -- VISUAL ASTRONOMY OF THE DEEP
Page 99 and 100: --- -- M83 (NGC 5236), GALAXY IN HY
Page 105 and 106:
VISUAL ASTRONOMY OF THE DEEP SKY A
Page 107 and 108:
--- VISUAL ASTRONOMY OF THE DEEP SK
Page 109 and 110:
--- -- VISUAL ASTRONOMY OF THE DEEP
Page 111 and 112:
---------------- 5 / --------______
Page 113 and 114:
Page 115 and 116:
VISUAL ASTRONOMY OF THE DEEP SKY --
Page 117 and 118:
-- VISUAL ASTRONOMY OF THE DEEP SKY
Page 119 and 120:
-- -- VISUAL ASTRONOMY OF THE DEEP
Page 121 and 122:
Page 123 and 124:
-- MI5 (NGC 7078), GLOBULAR CLUSTER
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
-- VISUAL ASTRONOMY OF THE DEEP SKY
Page 133 and 134:
-- ·rl E I u L ro 5 +J Q) (f) 0 Y
Page 135 and 136:
-- --- VISUAL ASTRONOMY OF THE DEEP
Page 137 and 138:
VISUAL ASTRONOMY OF THE DEEP SKY NG
Page 139 and 140:
'2 5 -rl E I U L CO '---' -t-J ill
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VISUAL ASTRONOMY OF THE DEEP SKY AP
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VISUAL ASTRONOMY OF THE DEEP SKY Ta
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Page 149 and 150:
-- Appendix E A catalog of deep-sky
Page 151 and 152:
Page 153 and 154:
-- -- --- VISUAL ASTRONOMY OF THE D
Page 155 and 156:
--- --- VISUAL ASTRONOMY OF THE DEE
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
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-- -- VISUAL ASTRONOMY OF THE DEEP
Page 167 and 168:
-- APPENDIX F: OPTIMUM DETECTION MA
Page 169 and 170:
------- VISUAL ASTRONOMY OF THE DEE
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VISUAL ASTRONOMY OF THE DEEP SKY -
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VISUAL ASTRONOMY OF THE DEEP SKY -
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G VISUAL ASTRONOMY OF THE DEEP SKY
Page 185 and 186:
INDEX INDEX M70 (NGC 6681), 312, 31
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OF THE ROGER N. CLARK

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