The Caldwell Objects

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33 & 34 to see such color in dim nebulosity, but aperture certainly helps, as does a narrowband filter favoring the nebula's fine-tuned emissions. Overall, the nebula's structure reminded me of coils of DNA. Of course, to the peering eye of the Hubble Space Telescope even a tiny section of the Veil Nebula is inconceivably intricate, looking like a close-up photograph of colored smoke rising from an unseen cigarette. HST imaged an area where the supernova blast wave recently hit a cloud of denser-than-average interstellar gas. After comparing the HST image to a 1953 Palomar Observatory photograph, two Johns Hopkins University scientists recently concluded that the Veil is a good deal younger (about 5,000 years old) and closer to Earth (about 1,400 lightyears) than widely believed. However, these revisions depend on a still-incomplete understanding of shock-wave propagation in the interstellar medium, and they have yet to gain universal acceptance. Once you have contemplated the Veil Nebula's details to your eye's delight, return to low power and try to glimpse two fainter wisps inside the main loop. The westernmost wisp is the more prominent of the two. Look for a triangular "head" on the north end of this tadpolelike feature. Can you see the tadpole's "tail," at the southern end, curve northward? From a dark site, the entire inner arc is prominent enough to fool an unwary observer into believing that he or she has seen the Veil's easternmost segment. The perceived dimensions of these fainter, enclosed features are tentative because they tend to follow star streams, and it is hard to judge where the nebulosity ends and the star streams begin. Like you, no doubt, I have wondered how the various names associated with this nebula came about. None of the names appear to be associated with pre-photographic (i.e., purely 134 visual) descriptions. William Herschel wrote of "branching nebulosity" that "divides into several streams," while the Rev. T W Webb . simply refers to NGC 6992 as a "large nebulosity in a curve" and to NGC 6960 as a "nebulous ray." The terms "Network Nebula" and "Filamentary Nebula," however, were in use at the beginning of the 20th century. They ostensibly describe the appearances of the eastern and western segments, respectively, on high-resolution photographic plates. Writing about the "Nebular Hypothesis" in his 1914 work The Problem of Volcanism, Joseph R Iddings discusses several "[c]louds of luminous matter. . . separated by rifts of darkness whose character is unknown." Among them is "another great cloud-like nebula of this kind . . . the 'network' nebula in Cygnus." His use of quotation marks reveals that "Network Nebula" was already in use by the 1910s. Iddings goes on to describe the nebula as "a cirrus cloud of inconceivable extent." Iddings, then, might have been the first person to associate the nebula with Cirrus, another occasionally invoked moniker. In his popular 1938 work Astronomy, Forest Ray Moulton describes the nebula's appearance on a wide-field plate by Lowell Observatory astronomer Wilbur A. Cogshall as "Veil-like"; his may have been the earliest use of that term. Indeed, by 1957 the "Veil" was the common name used by Bart Bok for NGC 6960. "Cygnus Loop" was bestowed upon the nebula after Rudolph Minkowski photographed the entire supernova remnant with the 48-inch Schmidt camera on Palomar Mountain. The names, then, appear to follow progress in astrophotography. By the way, supernovae occur in our galaxy roughly once every hundred years on average, which suggests that we are well overdue for another. So keep your eyes peeled to the night sky, or, as Jack Horkheimer, TV's Star Gazer, would say, "Keep looking up!" Deep-Sky Companions: The Caldwell Objects
35 NGC 4889 Type: Elliptical Galaxy (E4) Con: Coma Berenices The Caldwell Objects RA: 13 h 00 m 08 s Dec: +27° 58.5' Mag: 11.5 35 135
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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
Page 101 and 102: 2 0 North America Nebula NGC 7000 T
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Page 107 and 108: 2 1 Box Galaxy NGC 4449 Type: Irreg
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Page 115 and 116: 1003, NGC 1023, and NGC 1058 (a nic
Page 117 and 118: Way) that pop in and out of view as
Page 119 and 120: RA: 03 h 19 m 48 s Dec: +41° 30.7'
Page 121 and 122: Through the 4-inch, NGC 1275 is les
Page 123 and 124: (300,000 light-years), Pal 4 (360,0
Page 125 and 126: 26 Silver Needle Galaxy NGC 4244 Ty
Page 127 and 128: 2 7 Crescent Nebula NGC 6888 Type:
Page 129 and 130: Observatory, England) still lists a
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Page 133 and 134: 29 NGC 5005 Type: Mixed Spiral Gala
Page 135 and 136: s h a edges. r p However, Christian
Page 137 and 138: ulars; challenge yourself and your
Page 139 and 140: NGC 7331 is extended much farther t
Page 141 and 142: away" stars escaped the confines of
Page 143 and 144: sweep the telescope in a north-sout
Page 145 and 146: highly suspect by some. However, in
Page 147 and 148: 33 Network Nebula; Bridal Veil Nebu
Page 149 and 150: A quarter-second later, the star en
Page 151: under the dark skies of Seagrave Ob
Page 155 and 156: magnitude 12.2 some 18' to the east
Page 157 and 158: 36 NGC 4559 Type: Mixed Spiral Gala
Page 159 and 160: Comae Berenices, the obvious northe
Page 161 and 162: 3 7 NGC 6885 Type: Open Cluster Con
Page 163 and 164: pressed, stars of magnitude 6 to 11
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Page 173 and 174: not be found in planetary nebulae,
Page 175 and 176: 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
Page 183 and 184: magnitude field star 2' to the nort
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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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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5 4 NGC 2506 Type: Open Cluster Con
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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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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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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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