The Caldwell Objects

faintest of the five major members of the Sculptor
Group, the detail it displays in small instruments
makes it a superb, yet visually challenging, target
for beginners. If we accept a distance of 9 million
light-years for NGC 7793, its true linear diameter
is 23,000 light-years. We see its disk inclined 50°
from face on, so its tiny nuclear bulge and
dominating spiral arms are prominendy
revealed.
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N G C 3 6 2 1
T y S p e G i : a r l ( a S a l d x ) y
C o H n y : d r a
RA: 11 h 18.3 m
Dec: -32° 49'
Mag: 8.9
SB: 12.9
Dim: 14.9' x 7.4'
Dist: 23 million light-years
Hydra is host to innumerable galaxies, many of
which can be picked up in small amateur
instruments. Its biggest deep-sky prizes, of
course, are M83, a magnificent spiral galaxy, and
NGC 3242 (Caldwell 59), the Ghost of Jupiter
planetary nebula. Spiral galaxy NGC 3621 is
another bright denizen of Hydra, but very little
attention has been paid to it. The galaxy is not
included in many popular handbooks, though it
is similar in size to M83 (albeit nearly 1½
magnitudes fainter). In a 1993 Astrophysical
Journal article NGC 3621 was referred to as
"another comparatively poorly studied galaxy
despite having a large angular size and
abundance of ΗII regions." Once again, the low
southerly declination and a lack of bright nearby
stars may explain the neglect.
To find NGC 3621 look 10° south and
slightly east of Beta (β) Crateris and 3¼° west
and slightly south of Xi (ξ) Hydrae. Tele-
440
scopically, the galaxy appears as a big diffuse
glow with a bright core and a faint, elliptical halo.
Its spiral arms are faint and will challenge smalltelescope
users. The galaxy is reasonably large
(100,000 light-years across) and the universe's
expansion is carrying it away at a speed of 730
km per second. In long-exposure photographs
NGC 3621 is a remarkable pinwheel just 25° from
edge on. Its small, bright nucleus is nestled in a
bright ellipse of spiral arms (cut by rifts of dust)
that gradually unwind into a fainter outer halo.
One prominent arm extends southward from the
small bulge; it carries some of this galaxy's most
luminous ΗII regions.
16
N G C 1 3 4
T y M p i e S x : p e G i d a r l ( a S x l A y B b c )
C o S n c : u l p t o r
RA: 00 h 30.4 m
Dec: -33° 15'
Mag: 10.4
SB: 13.3
Dim: 7.6' x 1.5'
Dist: 62 million light-years
NGC 134 is an extraordinary nearly edge-on
spiral galaxy in Sculptor, which just happens to
be surrounded by, and somewhat lost among, a
cast of extragalactic prima donnas — namely
NGC 253 (Caldwell 65), NGC 300 (Caldwell 70),
and NGC 55 (Caldwell 72) — all of which are
savagely beautiful galaxies for small telescopes.
Nevertheless, NGC 134 is a treasure that's
relatively easy to acquire. First locate 4thmagnitude
Alpha (α) Sculptoris, which is some
12° south-southeast of Deneb Kaitos, or Beta (β)
Ceti. Next, use binoculars to locate 5thmagnitude
Eta (η) Sculptoris about 7½°
southwest of Alpha Sculptoris. Now center
Deep-Sky Companions: The Caldwell Objects