The Caldwell Objects

65
65
Great Sculptor Galaxy;
Silver Coin
NGC 253
Type: Mixed Spiral Galaxy
(SABc)
Con: Sculptor
RA: 00 h 47.6 m
Dec:-25° 17'
Mag: 7.6; 7.1 (O'Meara)
Dim: 25.8' x 5.9'
SB: 13.2
Dist: 9.8 million light-years
Disc: Caroline Herschel, 1783
W. H ERSCHEL: [Observed 30 October 1783] Considerably
bright, much extended, from south preceding to north
following [from southwest to northeast]. Much brighter in the
middle. Above 50' long and 7 or 8' broad. Discovered by
Caroline Herschel. (H V-1)
"STUNNING!" "SPECTACULAR!" "INCREDIBLE!" So
many adjectives have been used over the years to
describe NGC 253 that it's difficult to find others
more appropriate. In photographs the impression
is one of magnificent animation, of clumps of
starlight and dust stirred together in a stew of
galactic vapors. At a glance the galaxy looks like
the beginning of universal order emerging from
simmering chaos. And in a way it is. NGC 253 is
a somewhat normal, somewhat barred spiral,
with a complex lens centered on a tight central
core that has some of the densest knots of stars
ever found. A bar cuts across the lens and is
encircled by a bright elliptical ring of stars and
dust, off of which fly two spiral arms — one to
the northeast and one to the southwest, like two
propeller blades. In the notes that accompanied
William
258
GC: Remarkable, very bright, very large, very much extended
toward position angle 54°, 30' long, gradually brighter towards
the middle, four stars.
NGC: Remarkable, very bright, very large, very much extended
toward position angle 54°, gradually brighter in the middle.
Herschel's first catalog of "New Nebulae," the
great observer wrote of NGC 253: "This nebula
was discovered by my sister Caroline Herschel,
with an excellent small Newtonian sweeper of 27
inches focal length, and a power of 30.1 have
therefore marked it with the initial letters, C.H. of
her name." NGC 253 is one of at least 13 objects
Caroline discovered while sweeping the heavens
for comets in 1782 and 1783. William and
Caroline had the disadvantage of trying to study
this galaxy close to the horizon. However,
William's son, John, observed it high in the sky
from the Cape of Good Hope with an 18/ -inch 4
speculum-metal reflector. On November 20,1835,
he noticed that NGC 253 is "somewhat streaky
and knotty in its constitution and may perhaps be
resolvable."
At a distance of 9.8 million light-years,
Deep-Sky Companions: The Caldwell Objects