The Caldwell Objects

13
NGC 288
Type: Globular Cluster
Con: Sculptor
RA: 00 h 52.8 m
Dec: -26° 35'
Mag: 8.1
Diam: 13'
Dist: 27,000 light-years
Globular cluster NGC 288 resides near one of the
southern sky's greatest attractions — the oblique
spiral galaxy NGC 253 (Caldwell 65). Although
the globular lies only 1¾° to the southeast of the
galaxy, that's just about ¾° too far to be placed in
the same low-power field as NGC 253 in many
modern telescopes. But with a field of view
nearly 3° wide, the Genesis removes NGC 288
from the shadows of obscurity and thrusts it into
the telescopic "spotlight." And there are few
sights in the sky as rewarding as this dramatic
pairing of deep-sky splendors. Curiously, Patrick
Caldwell Moore did not include NGC 288 in his
catalog, and Robert Burnham Jr. fails to highlight
it in his Celestial Handbook, even in passing. The
Rev. T W Webb . acknowledges NGC 288 in his
Celestial Objects for Common Telescopes, though he
simply calls it "bright."
Both NGC 253 and NGC 288 can be easily
spotted in 7x35 binoculars, shining at 7th and 8th
magnitude, respectively. NGC 288 is less than 9°
southeast of Beta (β) Ceti (Deneb Kaitos), 3°
northwest of Alpha (α) Sculptoris, and just 40'
north and slightly east of the South Galactic Pole.
The cluster looks like a perfect sphere at 23x and
starts to resolve into individual stars at 72x (the
cluster's brightest member shines at magnitude
12.6), especially at the fringes, which become
patchy with clumps of
starlight. High power reveals many veins both
dark and bright emanating from a hollow central
wedge of stars. In larger telescopes the cluster is
quite remarkable. Christian Luginbuhl and Brian
Skiff compare their view of NGC 288 through a 12inch
reflector to that of the great globular M4 in
Scorpius, though they admit it is not as rich.
14
NGC 7793
Type: Spiral Galaxy (Sdm)
Con: Sculptor
RA: 23 h 57.8 m
Dec: -32° 35'
Mag: 9.2
SB: 13.6
Dim: 9.2' x 6.4'
Dist: 9 million light-years
NGC 7793 is a fine galaxy hidden in the star-poor
region of southwestern Sculptor. It lies some 13°
east-southeast of brilliant Fomalhaut, Alpha (α)
Piscis Austrini, and is near the apex of a nearly
perfect isosceles triangle whose other corners are
the magnitude-4.4 stars Beta (β) Sculptoris (7¼° to
the southwest of the galaxy) and Gamma (γ)
Sculptoris (8° to the west). The galaxy is a
prototypical late-type spiral, and it is receding
from us at a speed of 230 km per second.
Through the Genesis at 23x the 9th-mag-nitude
galaxy appears quite large, and it looks very
much like the smoothly textured head of a comet.
At 72x the galaxy's core appears sharply stellar;
the bright haze immediately surrounding the
core is dappled with fuzzy clumps that would
cause any small-telescope user to believe he or
she has chanced upon a globular cluster near the
limit of resolution. The galaxy's fainter outer
envelope is slightly elliptical and shows less
mottling. Although NGC 7793 is the
Twenty Spectacular Non-Caldwell Objects 439