Monoceros (abbr. Mon, gen. Monocerotis)
The Unicorn; a dim constellation that lies
across the celestial equator; it is bounded roughly by a great triangle
of brilliant stars: Sirius, Procyon, and Betelgeuse. Monoceros was first
brought into general use as a constellation by Jakob Bartsch,
son-in-law of Johannes Kepler, and is an area that abounds in open clusters
and faint nebulae. Among its most interesting deep sky objects are the Cone
Nebula, the Rosette Nebula, Hubble's
Variable Nebula (NGC 2261), and the open
clusters M50 (NGC 2323), near the border with
Canis Major, and the Christmas
Tree Cluster (NGC 2244). The Monoceros Loop is a filamentary
loop nebula, part of a 300,000-year-old supernova
remnant, about 3,000 light-years away in the galactic plane northeast
of the Rosette.
Alpha Mon, an orange giant star, is outshone both in magnitude and interest
by its constellation companion Beta. One
of the gems of the sky, Beta Mon was regarded by William Herschel
as "one of the most beautiful sights in the heavens." Beta is
a stunning triple system, consisting of three white or blue-white stars
of magnitude 4.5, 5.2 and 5.6. Delta, a magnitude 4.2 blue-white star lying
210 light years distant, forms a nice optical pairing with a magnitude 5.5
star. Epsilon is an easy double star in small telescopes, its yellow and
blue components of magnitude 4.5 and 6.5 making a fine contrast. See below
for details of the constellation's brightest stars and interesting deep
sky objects.
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Monoceros. © 2003 Torsten Bronger.
Copied here under the terms of the GNU Free Documentation License
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| Stars brighter than magnitude 4.0 |
| Star |
Visual
mag. |
Abs.
mag. |
Spectral
type |
Distance
(lt-yr) |
R.A. (h m s) |
Dec. ( ° ' '' ) |
| Beta |
3.76 |
-2.87 |
B3Ve |
691 |
06 28 49 |
-07 01 58 |
| Alpha |
3.94 |
0.71 |
K0III |
144 |
07 41 15 |
-09 33 04 |
| Gamma |
3.99 |
-2.49 |
K3III |
645 |
06 14 51 |
-06 16 29 |
| Other objects of interest |
| Name |
Type of Object |
Notes |
| Cone Nebula |
diffuse nebula |
See separate entry |
| Rosette Nebula |
diffuse nebula |
See separate entry |
| M50 |
open cluster |
NGC 2323. See separate entry |
| Christmas
Tree Cluster |
open cluster |
NGC 2244. See separate entry |
| NGC 2301 |
open cluster |
80 stars of 8th magnitude; diameter of 12'. A fine
sight in binoculars.
R.A. 06h 51m 45s; Dec. 00° 27' 33'' |
Hubble's
Variable Nebula |
reflection cluster |
NGC 2261. See separate entry |
Related categories
NOTABLE
STARS NEBULAE
AND STAR CLUSTERS GALAXIES
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