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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

¡

`

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