Image Credit & Copyright: Rolf Geissinger
It’s that time of year where, like Halloween we gotta come up with an obligatory Christmas space post and what better than the Christmas Tree Cluster? Some people call this the Christmas Tree Nebula and that’s ok but it’s cataloged by the cluster NGC 2264 which is embedded in the diffuse nebula, roughly 3000 light years away in the constellation of Monoceros (The Unicorn). This region is beautiful, full of objects, details and appropriately named because it’s loaded with color and you don’t have to stretch those egg nog induced imaginations too far to see the Christmas tree shape to the overall structure.
This image spans three-quarters of a degree or about 1.5 full moon widths and stretches about 40 light years in length. There are roughly (everything’s roughly) 40 stars that, with the help of the nebula, form a pretty well defined tree shape and many of these stars you can see without any optical aid at all. The naked eye visible 6th magnitude star HD 47887 sits just above the top of the tree, near the Cone nebula (the Cone nebula basically points at it) while S-Mon or 15 Monocerotis, at magnitude 4.5 is the brightest star in the cluster and sits at the base of the cluster.
Within this region of thick gas, dust and newborn stars are a few other notable locations such as the Fox Fur nebula and the Cone nebula (mentioned above) which we will detail next.
NOTE: NGC 2264 also includes the Cone nebula, not just the open star cluster.
NAME: NGC 2264, Christmas Tree Cluster, Snowflake Cluster, Fox Fur nebula, Sh2-273, Cone Nebula, NGC 2661, Hubble’s Variable Nebula.
WHAT IS IT?: Open star cluster and emission nebula.
HOW BIG IS IT?: The Christmas tree region is about 40 light years in diameter.
HOW FAR AWAY IS IT?: Roughly 3000 light years away.
DISCOVERY & NAMING: William Herschel in 1784 and named by L.S. Copeland.
APPARENT MAGNITUDE: The open star cluster is about +4.5.
WHERE IS IT? (General): Constellation Monoceros (The Unicorn).
WHERE IS IT? (Exact RA/DEC J2000): Star S-Mon RA 06h 40m 58.66s / DEC +09° 53′ 44.715″.
Rolf Geissinger: http://stern-fan.de/Seiten/frameset_eng.htm
NASA APOD for this image: http://apod.nasa.gov/apod/ap120410.html