NGC 2232
NGC 2316
NGC 2302
NGC 2311
NGC 2182
NGC 2301
NGC 2236
NGC 2251
NGC 2245
NGC 2247
CRL 915
NGC 2286
a
Betelgeuse
IC 2177
NGC 2170
NGC 2244
NGC 2237
¡
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NGC 2261
NGC 2264
WWW.ASTRONOMY.COM 61
Monoceros
The imager
processed this
photograph so
it highlights
the stars in the
constellation
Monoceros and
subdues the
ones outside
its borders.
TONY HALLAS The Cone Nebula
The Cone Nebula (NGC 2264) is an emission nebula that
pairs with an open cluster called the Christmas Tree
Cluster. BOB FERA
Hubble’s
Variable Nebula
Hubble’s Variable Nebula
(NGC 2261) is a fascinating
reflection nebula
associated with
the variable star
R Monocerotis. It appears
triangular, almost comet-
like, with the “head”
pointing southward.
The nebula’s brightness
looks even across its face, and, except for the northern
side, all edges seem sharp. CAROLE WESTPHAL/ADAM BLOCK/NOAO/AURA/NSF
The Rosette
Nebula
The Rosette Nebula
(NGC 2237–9/46) isn’t
a single object. From
a dark site, you’ll first
spot NGC 2244. A
4-inch scope reveals
two dozen stars in an
oval region. To best
observe the nebula,
use a magnification
of 50x and insert a nebula filter to dim NGC 2244’s
stars. The nebula’s western side appears brighter, but
its eastern side is much wider. A nebulous wall with a
well-defined border forms its northern edge. ERIC AFRICA
NGC 2170
To observe this reflection nebula,
look 1.8° west of magnitude 4.0
Gamma (γ) Monocerotis. Through
an 8-inch telescope, you’ll see a
bright circular haze that surrounds
a magnitude 9.5 star. NGC 2182, a
similar object, lies only 0.5° east. It
appears fainter than NGC 2170 and
surrounds a magnitude 9.3 star. ADAM
BLOCK/MOUNT LEMMON SKYCENTER/UNIVERSITY OF ARIZONA
The Seagull Nebula
The Seagull Nebula (IC
2177) is huge (2° by 0.7°),
so it looks best through
a telescope/eyepiece
combination that gives
a wide field of view. A
nebula filter will help a lot.
Note the starry chains that
extend along the length
of the nebula. VANCE BAGWELL
NGC 2506
Through a 4-inch scope,
the stars of this open
cluster all appear to
be about the same
brightness, but they
have a wildly uneven
distribution. Use a
magnification of 150x,
and you’ll see a clumpy
center and streamers,
spiral “arms,” letters,
and more. Move up to a 12-inch scope at 200x, and the
same 30 or 40 stars you saw through the smaller aperture
now hang before a background glow that glistens like a
diamond-encrusted black velvet sheet. MARTIN C. GERMANO