The Caldwell Objects

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86 With averted vision it immediately resolves into a granular sphere of crushed diamonds with brighter jewels seemingly tossed helter-skelter about its periphery. About two dozen of the cluster's suns shine between 10th and 12th magnitude. At 72x the cluster looks more cometlike; though the core is circular, a bright tail of mixed suns tapers off to the east-northeast. Aside from the round center, this tail is the single most prominent stellar gathering in the entire cluster. An arrow of four 11th- to 344 12th-magnitude suns appears opposite the tail to the west-southwest. One meandering arm courses south to a 10th-magnitude sun, while a weaker string of stars points northwest. The remaining suns in the periphery form all manner of shapes: arcs, right angles, Ts, hooks, circles. What appears is a dizzying array of chaos. It looks as if the cluster's center of gravity suddenly ceased to exist, allowing it to fly apart. High magnification will help you plumb the 2.5'-wide core. Deep-Sky Companions: The Caldwell Objects
8 7 NGC 1261 Type: Globular Cluster Con: Horologium RA: 03 h 12 m 15.3 s Dec: -55° 13'01" Mag: 8.3 Diam: 6.8' Dist: 55,500 light-years Disc: James Dunlop, included in his 1827 catalog J. H ERSCHEL: Bright; large; irregularly round; 2.5' diameter; all resolved into equal stars [of] 14 [th] magnitude. Has a star [of] 9th magnitude [at a position angle of] 45 [degrees] north following [to the northeast]. 3' distant. (h 2517) O UR NEXT C ALDWELL OBJECT, NGC 1261, is an unobtrusive globular cluster inhabiting an inconspicuous swath of celestial real estate in the unassuming constellation of Horologium, the Clock. Aside from its 4th-magnitude lucida, Alpha (α) Horologii, that constellation is but a dim sprinkling of 5th- and 6th-magni-tude suns paralleling the southeastern bank of the celestial River Eridanus. The Abbe Nicolas Louis de Lacaille created the constellation during his famous exploration of the southern skies from the Cape of Good Hope between 1751 and 1753. But, as Julius Staal reminds us in The New Patterns in the Sky, Lacaille named the constellation Horologium Oscillatorium, the Pendulum Clock. Lacaille wanted to commemorate the technological achievement of not the clock but the pendulum, which was designed to make the clock run more accurately. Unfortunately, as time marched on, it became popular to refer to the constellation as simply Horologium. In doing so we have denied The Caldwell Objects GC/NGC: Globular cluster, bright, large, round, partially resolved, some stars seen. 87 ourselves a vital piece of astronomical history. The best way to find NGC 1261 is to start at lstmagnitude Achernar (α Eridani). Some 6° to the north-northeast are the roughly 4th-magnitude stars Chi (χ) and Phi (φ) Eridani. Now use your binoculars and look 3½° southeast of Phi Eridani for a 2°-long acute triangle comprising 5thmagnitude Eta (η) and Zeta (ζ) Horologii and a 6th-magnitude star. (Zeta Horologii marks the southern tip of that triangle.) Next, look a little more than 2° southeast of Zeta Horologii for a 1°wide right triangle of magnitude-6.7 stars. (Finding these triangles should not be a problem because they contain the brightest stars in their respective sky regions.) At this point it may be best to switch to your telescope and put in a wide-field eyepiece, because NGC 1261 shines weakly at magnitude 8.3 and its disk is small and compact. You'll find it just shy of 2° due east of the 1°-wide triangle. TW Horologii, a semiregular variable star that fluctuates between magnitudes 345
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DEEP-SKY COMPANIONS The Caldwell Ob
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DEEP-SKY COMPANIONS The Caldwell Ob
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Contents Foreword by Patrick Moore
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to be more difficult than others, s
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years of thought and observation ar
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XII position, type, angular size, a
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sky and share its splendors. There
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CHAPTER 1 About This Book O N ONE S
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times vog can back up and cause a s
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when there is moisture in the air.
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Herschel's original observations, p
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we use today and to one another? I
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SIMBAD (Set of identifications, Mea
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Caldwell 26. The objects in the Cal
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tion near the edges of the charts).
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nights of observing. Unless otherwi
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CHAPTER 2 The Caldwell Objects 1 1
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Because of its location far from th
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as strongly energized as would be e
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suggested by the patchiness of NGC
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4 NGC 7023 Type: Reflection Nebula
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astronomers found direct evidence o
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and his contemporaries. Why then wa
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6 Cat's Eye Nebula NGC 6543 Type: P
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Eighth-magnitude NGC 6543 is locate
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7 NGC 2403 Type: Mixed Spiral Galax
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according to theory, the gas densit
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8 Ghost’s Goblet NGC 559 Type: Op
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One other thing adds to the cluster
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RA: 22 h 56.8 m Dec: +62° 37' Mag:
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nebula is a near impossibility, eve
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1 0 The Horseshoe Cluster NGC 663 T
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heart of the cluster, dividing it i
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appears to be the edge of a rapidly
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1 2 NGC 6946 Type: Mixed Spiral Gal
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to the west by a row of similarly b
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the south-southwest. NGC 457, howev
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photographs. The cluster's bright "
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play begins at 8:00 p.m., when my e
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ightness by summing the contributio
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jewels. Here are sapphires, rubies,
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15 outer shell falls upon the retin
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"knots" have also been noted by exp
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tight gathering of a half-dozen rou
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1 7 NGC 147 Type: Elliptical Galaxy
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the center. A faint outer halo is a
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1 9 Cocoon Nebula IC 5146 (nebula)
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trickle into the pool surrounding t
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2 0 North America Nebula NGC 7000 T
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egion's size and mass extreme when
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The Caldwell Objects 20 87
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2 1 Box Galaxy NGC 4449 Type: Irreg
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fuse but obvious glow of patchy lig
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qualifier—the word "light" — ha
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with a sheen of light, especially a
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1003, NGC 1023, and NGC 1058 (a nic
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Way) that pop in and out of view as
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RA: 03 h 19 m 48 s Dec: +41° 30.7'
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Through the 4-inch, NGC 1275 is les
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(300,000 light-years), Pal 4 (360,0
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26 Silver Needle Galaxy NGC 4244 Ty
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2 7 Crescent Nebula NGC 6888 Type:
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Observatory, England) still lists a
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pie refractors and inefficient spec
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29 NGC 5005 Type: Mixed Spiral Gala
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s h a edges. r p However, Christian
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ulars; challenge yourself and your
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NGC 7331 is extended much farther t
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away" stars escaped the confines of
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sweep the telescope in a north-sout
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highly suspect by some. However, in
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33 Network Nebula; Bridal Veil Nebu
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A quarter-second later, the star en
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under the dark skies of Seagrave Ob
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35 NGC 4889 Type: Elliptical Galaxy
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magnitude 12.2 some 18' to the east
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36 NGC 4559 Type: Mixed Spiral Gala
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Comae Berenices, the obvious northe
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3 7 NGC 6885 Type: Open Cluster Con
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pressed, stars of magnitude 6 to 11
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of Herschel's telescope. W then e e
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see the dark needle near the third
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sion of a "thin flat ring of enormo
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(which does not appear on Sky Atlas
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not be found in planetary nebulae,
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star in a large naked-eye triangle
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4 0 NGC 3626 Type: Lenticular Galax
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40 NGC 4546 in Virgo, NGC 4138 in C
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Northern Hemisphere, and people cel
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magnitude field star 2' to the nort
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this state of affairs.) The Hyades
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4 2 NGC 7006 Type: Globular Cluster
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each square arcminute of its disk s
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4 3 Electric Arc NGC 7814 Type: Spi
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hook as my "train route." Start at
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230 billion Suns and a physical dia
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4 5 NGC 5248 Type: Mixed Spiral Gal
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of the field. Those living under da
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1" in a mere four days. Clearly, La
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porarily) even the most practiced o
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4 7 NGC 6934 Type: Globular Cluster
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stragglers are stars that appear to
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4 8 NGC 2775 Type: Spiral Galaxy (S
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with a CCD camera — discovered a
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this wreathlike network of dust and
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fuzzy patch of light with the unaid
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known as NGC 2244; and NGC 2239 sho
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At a glance the two stars at the cl
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On four plates taken with the Bruce
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years. A total of 43 star-cluster c
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5 2 NGC 4697 Type: Elliptical Galax
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northeast of the sixth star in the
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53 The Spindle NGC 3115 Type: Lenti
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and the 100-inch telescopes atop Mo
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emerge, followed by a diffuse outer
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perfection than is actually the cas
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jets, like a stream of water from t
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5 6 Pac-Man Nebula NGC246 Type: Pla
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the triple-alpha process, wherein t
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5 7 Barnard's Galaxy NGC 6822 Type:
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to show how the galaxy's western re
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core and limber arms, which, he wro
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esembles Jupiter . . . '" Smyth's f
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years" and suggests amateurs monito
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6 0 Ringtail Galaxy; Rataail Galaxy
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war. X-ray images taken by the Rosa
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W. Sinnott's NGC 2000.0 has a visua
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62 Milkweed Seed Galaxy NGC247 Type
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through the narrow haze. But give t
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was more readily seen in binoculars
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Society. Accepting that distance, w
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any large telescope that can provid
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ought it to our attention in the Fe
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inch the cluster shows a pyramid of
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NGC 253 is the brightest member of
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magnitude stars, one just to the ea
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6 6 NGC5694 Type: Globular Cluster
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you see its core dancing? Its starl
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cosmologist Halton Arp (Max-Planck
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and kinked. All this detail is wrap
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telescope. But seeing it takes more
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streamers begin to appear, but they
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tounding, because NGC 6302 is a mag
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70 Southern Pinwheel NGC300 Type: S
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would John Herschel suddenly fault
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Dunlop discovered NGC 55 with his 9
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even when crossing the meridian. Co
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"nebulous clusters" (Class II); and
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galaxy's disk and halo. NGC 2477 ap
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condensed, almost to the very margi
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The asymmetry remains at high power
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Page 361: much sky as does the full Moon, tho
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Page 379 and 380: 9 2 Eta Carinae Nebula GC 3372 Type
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with the naked eye is a challenge.
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1 0 0 Lambda Centauri Cluster Colli
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position updates to (2000.0) R.A. 1
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Eta Carinae Nebula. But remember th
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9th magnitude. Of the latter, 23 ha
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103 1 0 3 Tarantula Nebula; True Lo
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southern-sky explorer Abbe Nicolas
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104 NGC 362 Type: Globular Cluster
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ters it has had thus far with the g
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ly east of NGC 362 we find the magn
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the eye ever inward and takes your
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1 0 5 Southern Butterfly NGC 4833 T
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stars"). Lacaille also likened NGC
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is about 7' in length, and nearly 2
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107 NGC 6101 Type: Globular Cluster
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evealed a significant blue-straggle
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ightest stars shine around 4th magn
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egion looks cold and disturbing, no
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The galaxy received some incidental
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This entry is obviously in error, b
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7 N G C 4 0 4 T y L p e n : G t a i
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pointed her 7x35 binoculars toward
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13 NGC 288 Type: Globular Cluster C
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your telescope on Eta Sculptoris an
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19 N G C 6 2 8 1 T y O p e C : n l
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C Name Type Con. R.A. Dec Mag. Size
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C Name Type Con. R.A. Dec Mag. Size
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Appendix B Why Messier Did N o t i
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A typical pattern for evening hunti
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Earth turns, the cluster would clim
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Initially Herschel made his living
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of the heavens with it. For his swe
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tube's front end. This meant that t
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Star in Collo Ceti" about the star
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years, Herschel would observe some
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fluid, but added that ages of obser
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Appendix D Photo Credits in order o
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A Abell426, 101 Acrux, 388, 392, 39
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index Caldwell 44, 173, 176-178 Cal
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and nebulae, 271, 274, 362 and open
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Hevelius, Johannes, 72, 81, 452 Hip
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M103, 49-50, 58-59 M110, 77 MACHOs.
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NGC 3324, 369 NGC 3372 (Caldwell 92
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Perseus Cluster, 101 Phi Cas Cluste
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Τ Tarantula Nebula (Caldwell 103),
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