The Caldwell Objects

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52 stars near the limit of vision? Or could this truly be the nominally elliptical galaxy's "hidden" disk? One problem with this theory is that I have seen this illusion with true ellipticals like M32. That being said, if NGC 4697's lenticular appearance is an illusion, it is an illusion shared with Texas deep-sky aficionado Barbara Wilson. Using a 20inch f/4 reflector at 72x, Wilson saw this "absolutely beautiful fabulous brilliant oval" with a "long wispy brightness like a barred spiral... so it's a huge oval with a long bar-type brightness through the center." Perhaps amateurs with CCD cameras can look for this bar— a feature presumably blown out in long-exposure photographs — to determine if it is real or an illusion caused by faint unresolved foreground stars. NGC 4679 appears to be interacting with a faint unnamed galaxy 5.9' to the west-northwest. This galaxy should be a challenge to observers with large telescopes. 210 Deep-Sky Companions: The Caldwell Objects
53 The Spindle NGC 3115 Type: Lenticular Galaxy (SO) Con: Sextans RA: 10 h 05.2 m Dec:-07° 43' Mag: 8.9 Dim: 6.9' x 3.4' SB: 12.1 Dist: 22 million light-years Disc: William Herschel, 1787 W. H ERSCHEL: [Observed 23 February 1787] Extremely bright, considerably large, much extended, 45° from south preceding to north following [from southwest to northeast]. Has a bright nucleus 2' long, faint [branch ?] 5' long. (Η 1-163) GC/NGC: Very bright, large, very much extended ONE OF THE MOST BEAUTIFUL GALAXIES IN the heavens awaits small-telescope users in the obscure southern constellation Sextans. NGC 3115, the famous Spindle, lies about 20° south of Regulus, but few amateurs point their telescopes at it. Sextans is a boxy southern constellation with stars no brighter than magnitude 4.5, which isn't a problem if you live under a dark sky. But if you have to contend with city or suburban lights, navigating that starless tract is like rowing a boat blindfolded. This is unfortunate, since NGC 3115 is a splendid object. It is essentially no farther south than the great Orion Nebula, and at upper culmination it is fully one-third of the way up the sky from horizon to zenith at midnorthern latitudes. At a glance it seems odd that NGC 3115 escaped Messier's careful gaze. After all, the galaxy is close to the ecliptic, placing it within the comet haystack scanned by most 18th-century comet hunters. In fact, Messier discovered The Caldwell Objects toward position angle 46°, very gradually then suddenly much brighter in the middle to an extended nucleus. 53 objects farther than NGC 3115 from the ecliptic. The galaxy is certainly obvious enough in today's instruments. In fact, NGC 3115 is a grander sight than many galaxies in Messier's list. So how did he "miss" it? Let's first consider what NGC 3115 would have looked like through Messier's lessthan-perfect telescopes. Messier used about a dozen different telescopes ranging from reflectors with inefficient speculum mirrors (the largest having an 8-inch aperture) to simple refractors with apertures up to 3½° inches. Certainly, the galaxy should have been easily discernible in a 6- or 8-inch telescope. But ponder these words by Adm. William Henry Smyth, who describes his view of NGC 3115 through a 6-inch refractor: "It is remarkable that this object was very clearly distinguished in my telescope; for [Herschel] says it was scarcely perceptible in his 20-foot when he gave it only six inches of aperture." Of course, the clear glass of Smyth's 6-inch refrac- 211
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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
Page 177 and 178: 4 0 NGC 3626 Type: Lenticular Galax
Page 179 and 180: 40 NGC 4546 in Virgo, NGC 4138 in C
Page 181 and 182: Northern Hemisphere, and people cel
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Page 185 and 186: this state of affairs.) The Hyades
Page 187 and 188: 4 2 NGC 7006 Type: Globular Cluster
Page 189 and 190: each square arcminute of its disk s
Page 191 and 192: 4 3 Electric Arc NGC 7814 Type: Spi
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Page 197 and 198: 4 5 NGC 5248 Type: Mixed Spiral Gal
Page 199 and 200: of the field. Those living under da
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Page 203 and 204: porarily) even the most practiced o
Page 205 and 206: 4 7 NGC 6934 Type: Globular Cluster
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Page 209 and 210: 4 8 NGC 2775 Type: Spiral Galaxy (S
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Page 217 and 218: known as NGC 2244; and NGC 2239 sho
Page 219 and 220: At a glance the two stars at the cl
Page 221 and 222: On four plates taken with the Bruce
Page 223 and 224: years. A total of 43 star-cluster c
Page 225 and 226: 5 2 NGC 4697 Type: Elliptical Galax
Page 227: northeast of the sixth star in the
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Page 233 and 234: 5 4 NGC 2506 Type: Open Cluster Con
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Page 241 and 242: 5 6 Pac-Man Nebula NGC246 Type: Pla
Page 243 and 244: the triple-alpha process, wherein t
Page 245 and 246: 5 7 Barnard's Galaxy NGC 6822 Type:
Page 247 and 248: to show how the galaxy's western re
Page 249 and 250: 5 8 NGC 2360 Type: Open Cluster Con
Page 251 and 252: core and limber arms, which, he wro
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Page 255 and 256: years" and suggests amateurs monito
Page 257 and 258: 6 0 Ringtail Galaxy; Rataail Galaxy
Page 259 and 260: war. X-ray images taken by the Rosa
Page 261 and 262: W. Sinnott's NGC 2000.0 has a visua
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Page 265 and 266: through the narrow haze. But give t
Page 267 and 268: was more readily seen in binoculars
Page 269 and 270: Society. Accepting that distance, w
Page 271 and 272: any large telescope that can provid
Page 273 and 274: ought it to our attention in the Fe
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Page 277 and 278: 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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other popular nickname, the Eight-B
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longed look, the object displays a
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times larger than the full Moon. In
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emains of a globular cluster that w
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he classified them accordingly. NGC
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NGC 6231). Under averted vision the
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7 7 Centaurus A NGC5128 Type: Pecul
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Harvard College Observatory's 24-in
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at 16 million light-years. If you s
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78 NGC 6541 Type: Globular Cluster
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seems to fragment into tiny stars,
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sense, evinced by any known cluster
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12th-magnitude double star. The clu
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original with Bayer, but goes back
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Omega Centauri is generally regarde
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glitter all come to mind as the clu
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shattered remains of their diminuti
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It's a nice even disk of l0th-magni
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with the fiery reddish light of hyd
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nebulosity when he viewed the regio
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the two jets of radio-wave-emitting
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pair of tweezers. A fairly bright s
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suggest that our universe may be on
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8 5 Omicron Velorum Cluster IC2391
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Nicolas Louis de Lacaille, however,
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much sky as does the full Moon, tho
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8 7 NGC 1261 Type: Globular Cluster
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timates, making it 2 billion years
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NGC 5822. Don't be surprised if you
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89 S Normae Cluster NGC 6087 Type:
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fact, if you look about 7' southwes
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lowing night fell clear, when Hersc
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NGC 2867 is a nitrogen-rich planeta
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halfway between M37 in Auriga (200
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9 2 Eta Carinae Nebula GC 3372 Type
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anch of cold, dark material. Indeed
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stretch 16 billion km from the cent
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the object was known to some civili
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east, and a dim lip of gas to the s
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1 0 1 NGC 6744 Type: Barred Spiral
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have been identified in NGC 6752's
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ightest spiral arm(s) to the north,
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his maiden voyage of discovery in 1
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simply takes much too much effort t
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9 5 NGC 6025 Type: Open Cluster Con
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very wide double of near-equal inte
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went out and looked at the cluster
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NGC 2516 is 60 million years young
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and contains some 1,890 members, wh
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9 8 Coalsack Cluster NGC 4609 Type:
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it near the Swan? There is a still
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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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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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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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