The Caldwell Objects

73
73
NGC 1851
Type: Globular Cluster
Con: Columba
RA: 05 h 14 m 06.3 s
Dec: -40° 02' 50"
Mag: 7.1
Diam: 12'
Dist: 39,400 light-years
Disc: James Dunlop, included in his 1827 catalog
J. H ERSCHEL: Superb globular cluster; all resolved into stars of
14th mag.; very suddenly much brighter in the middle to a
blaze or nucleus of light; [diameter] in RA = 15 seconds of time.
Difference of left and right eyes in resolving this cluster very
remarkable. Returning from the left to the right eye, the object
(in comparison) appears as if glazed over with a kind of dull
film, (h 2777)
C OVERING 270 SQUARE DEGREES OF SKY ,
Columba, the Dove, is the heavens' 54th-largest
constellation. It's a sprightly little group of stars
that pays homage, in part, to the bird that Noah
released from his Ark after the great flood; the
dove returned with an olive branch in his beak to
alert Noah that the waters were receding. Today
the bird stands on the western banks of the river
Milky Way, where it has been all but forgotten by
Northern Hemisphere observers. Yet the Dove's
heart — Alpha (α) Columbae (Phact), a suspected
variable star that burns at magnitude 2.6 — lies at
a respectable declination of -34°, which places it
11° above the horizon at upper culmination when
seen from a latitude of 45° north (and higher still
from more southerly locations). The constellation
lies directly south of Lepus, the Hare, which is
itself directly south of
288
GC: Globular cluster of stars, remarkable, very bright, very
large, round, very suddenly very bright in the middle,
resolvable.
NGC: Globular cluster of stars, remarkable, very bright, very
large, round, very suddenly very bright in the middle, well
resolved, clearly consisting of stars.
Orion, and three of Columba's brightest stars —
Alpha, Beta (β), and Epsilon (ε) Columbae — form
an obtuse 4°-long triangle visible to the unaided
eye a fist's width west-southwest of 3rdmagnitude
Zeta (ζ) Canis Majoris (Furud), the
Great Dog's hind paw. In his Star Names: Their Lore
and Meaning, Richard Hinckley Allen says that
Phact was important to Egyptian temple worship,
and a dozen temples might have been oriented to
this star.
While sweeping Columba with a 9-inch
reflector at Parramatta, New South Wales, lames
Dunlop picked up the fine nebulous glow now
known as NGC 1851 nearly 8° southwest of Alpha
Columbae and cataloged it as his 508th discovery:
An exceedingly bright, round, well-defined nebula,
about 1½' diameter, exceedingly
Deep-Sky Companions: The Caldwell Objects