Editing Monoceros (section)

===Deep-sky objects===
Part of the [[galactic plane]] goes through Monoceros, so background galaxies are concealed by [[interstellar dust]]. Monoceros contains many clusters and nebulae; most notable among them are:
* [[Messier 50]], an [[open cluster]]
* The [[Rosette Nebula]] (NGC 2237, 2238, 2239, and 2246) is a [[diffuse nebula]] in Monoceros. It has an overall magnitude of 6.0 and is 4900 light-years from Earth. The Rosette Nebula, over 100 light-years in diameter, has an associated star cluster and possesses many [[Bok globule]]s in its dark areas. It was independently discovered in the 1880s by [[Lewis Swift]] (early 1880s) and [[Edward Emerson Barnard]] (1883) as they hunted for [[comets]].{{sfn|Levy|2005|p=104}}
* The [[Christmas Tree Cluster]] (NGC 2264) is another open cluster in Monoceros. Named for its resemblance to a [[Christmas tree]], it is fairly bright at an overall magnitude of 3.9; it is 2400 light-years from Earth. The variable star S Monocerotis represents the tree's trunk, while the variable star [[V429 Monocerotis]] represents its top.{{sfn|Levy|2005|pp=82-83}}<ref name="NYT-20231219">{{cite news |last=Miller |first=Katrina |title=It's Christmastime in the Cosmos - Astronomers have a long tradition of finding holiday cheer in outer space. |url=https://www.nytimes.com/2023/12/19/science/christmas-stars-galaxies-webb-nasa.html |date=19 December 2023 |work=[[The New York Times]] |url-status=live |archiveurl=https://archive.today/20231219114751/https://www.nytimes.com/2023/12/19/science/christmas-stars-galaxies-webb-nasa.html |archivedate=19 December 2023 |accessdate=19 December 2023 }}</ref>
* The [[Cone Nebula]] (NGC 2264), associated with the Christmas Tree Cluster, is a very dim nebula that contains a dark conic structure. It appears clearly in photographs, but is very elusive in a telescope. The nebula contains several [[Herbig–Haro object]]s, which are small irregularly variable nebulae. They are associated with [[protostar]]s.{{sfn|Levy|2005|p=83}}
* [[NGC 2254]] is an open cluster with an overall magnitude of 9.7, 7100 light-years from Earth. It is a Shapley class f and Trumpler class I 2 p cluster, meaning that it appears to be a fairly rich cluster overall, though it has fewer than 50 stars. It appears distinct from the background star field and is very concentrated at its center; its stars range moderately in brightness.{{sfn|Levy|2005|p=85}}
* [[Hubble's Variable Nebula]] (NGC 2261) is a nebula with an approximate magnitude of 10, 2500 light-years from Earth. It is named for [[Edwin Hubble]], and was discovered in 1783 by Herschel. Hubble's Variable Nebula is illuminated by [[R Monocerotis]], a young variable star embedded in the nebula; the star's unique interaction with the material in the nebula makes it both an [[emission nebula]] and a [[reflection nebula]]. One hypothesis regarding their interaction is that the nebula and its illuminating star are a very early stage planetary system.{{sfn|Levy|2005|pp=105-106}}
*[[IC 447]], a reflection nebula.