This drawing, among other things, strongly suggests that the Rosette is a difficult object visually. Here are some details by the artist:

http://www.deepskywatch.com/Astrosketches/rosette-nebula-sketch.html

Nebula in the middle: "Rosette Nebula" (Caldwell 49) - HII star forming region.
Involves: NGC2237, NGC 2239, NGC 2238, NGC 2246, LBN 949. size: 1.4° -- magnitude: 9
Constellation: Monoceros. distance: 5.2 Kly.
Star cluster in the middle: open cluster NGC 2244 -- magnitude: 4.8

"To the east of the constellation Orion sits the little known and hard-to-see constellation called Monoceros. Its name is Greek for unicorn, and was probably penned by a Dutch cartographer named Petrus Plancius in the 17th century. In the unicorn’s head, which is immediately to the left of Orion’s chest, sits the Rosette Nebula. It appears on Earth to be 1 degree across, which is about 5 times the size of the full Moon and has an actual radius of 65 light years, although estimates vary. The nebula's apparent magnitude is a relatively dim 9, which is impossible to see with the unaided human eye.

The nebula's dimness made it rather difficult to discover. This large cloud of gas and dust sits about 5,000 light years from the Earth, although other estimates of the Rosetta Nebula's distance can be as low as 1,500 light years. It is composed mostly of hydrogen, but contains dust and other elements as well. The nebula is classified as an H II region, meaning that the gas has been ionized by by the intense light being emitted by stars that have formed in it. The huge amounts of gas in the Rosette Nebula are driving the formation of very large and bright O and B type stars. The extremely energetic solar wind from these stars has created an area roughly 3,000 cubic light years in volume at the nebula's center with a temperature of 6 million kelvins. This hot gas itself emits X-rays, and its discovery shed new light on how solar wind from massive stars interact to create violent shocks.

The Rosette Nebula itself is a part of the much larger Rosette Molecular Cloud, and is differentiated by its emission of light. It is further broken down into several smaller parts which have been assigned NGC numbers; 2237, 2238, 2239, and 2246. In the center of the nebula sits the open star cluster NGC 2244, fueling the extreme temperatures. This open cluster was discovered in 1690 by John Flamsteed, but the Rosette Nebula took much more effort to find. The various parts of the nebula were discovered by three different astronomers: John Herschel found 2239, Albert Marth found 2238, and Lewis Swift found 2237 and 2246." -- from BrightHub.com

Please use this labeled astrophotograph above to help find your way around this very interesting and complex area. If you rollover the image, a less-confusing non-labeled one appears. When I was exposing the shot(s), I was amazed at what came up. I framed the shot in large measure because I was able to make out the (upside-down) Christmas Tree open star cluster, relatively easily seen in the test photographs. I frankly was surprised to see the Cone Nebula and associated emission nebulae emerging as I took longer and longer exposures -- finally deciding on 500-seconds per exposure (a very long time). I was also very pleased to see the color differential between the red emission and dark obscuring Cone and blue reflection Foxfur Nebulae, not usually so obvious and apparently only easily ascertained under dark skies. I obtained 10 images, and combined them digitally as described elsewhere within this website and linked here. Click on the smaller, non-labeled image above right or the proceeding text to access the less-bothersome-uncluttered-by-arrows-and-verbiage final Cone Nebula region astrophotograph.

I also was quite surprised to see Hubble's Variable Nebula emerge so obviously from the darkness, and previous to the imaging session I had not even heard of the beautiful open star cluster designated Tr5 (Trumbler 5). I only accessed the more compete star charts including this plethora of deep sky objects after the astrophoto session.

"The Cone Nebula is a famous H II region located in the constellation Monoceros, the Unicorn. It lies at an approximate distance of 2,700 light years from Earth and is located in the Orion Arm of the Milky Way. The nebula is part of the larger star forming region around the Christmas Tree Cluster. The two objects share the designation NGC 2264 in the New General Catalogue. The Cone Nebula has an apparent length of 10 arcminutes, corresponding to a spatial extension of about 7 light years. It is faint when observed visually, but makes a stunning sight in long exposure photographs. The nebula forms the southern part of NGC 2264, while the Christmas Tree Cluster forms the northern. The entire region of NGC 2264 occupies an area of 20 arcminutes and has a visual magnitude of 3.9.

The Cone Nebula is relatively easy to find because it lies in a region that contains many bright stars. It is located in the northern part of Monoceros, north of the line drawn from Procyon in Canis Minor to Betelgeuse in Orion, and not far from the brighter Rosette Nebula. The Cone Nebula can be seen in 10-inch and larger telescopes under dark skies.

The giant pillar of gas and dust was named for its conical shape, which is a result of a dark nebula absorbing the light of an emission nebula that lies behind it. The faint emission nebula is illuminated by the star S Monocerotis, the brightest member of the NGC 2264 cluster. S Monocerotis (15 Monocerotis) is a massive variable star system that lies at the base of the Christmas Tree Cluster, believed to consist of up to eight components. Resembling a nightmarish beast rearing its head from a crimson sea, this monstrous object is actually an innocuous pillar of gas and dust. Called the Cone Nebula (NGC 2264) — so named because, in ground-based images, it has a conical shape — this giant pillar resides in a turbulent star-forming region.

The entire nebula is 7 light-years long. The Cone Nebula resides 2,500 light-years away in the constellation Monoceros. Radiation from hot, young stars has slowly eroded the nebula over millions of years. Ultraviolet light heats the edges of the dark cloud, releasing gas into the relatively empty region of surrounding space. There, additional ultraviolet radiation causes the hydrogen gas to glow, which produces the red halo of light seen around the pillar. A similar process occurs on a much smaller scale to gas surrounding a single star, forming the bow-shaped arc seen near the upper left side of the Cone. This arc, seen previously with the Hubble telescope, is 65 times larger than the diameter of our solar system. The blue-white light from surrounding stars is reflected by dust. Background stars can be seen peeking through the evaporating tendrils of gas, while the turbulent base is pockmarked with stars reddened by dust. Over time, only the densest regions of the Cone will be left. Inside these regions, stars and planets may form.

The Cone Nebula was likely formed by the wind from the massive star designated as NGC 2264 IRS. The radiation of the hot nearby stars illuminates and erodes the giant pillar of gas, while ultraviolet radiation is responsible for the pillar’s reddish glow. The infrared source NGC 2264 IRS is embedded within the dust and gas of the nebula and cannot be seen by optical telescopes. Hubble images taken in infrared light have revealed that the massive young star is surrounded by six very young, pre-main sequence stars with a mass almost that of the Sun, all found within less than a tenth of a light year of NGC 2264 IRS. NGC 2264 IRS is also known as Allen’s Source, after the astronomer D.A. Allen, who pointed out in 1972 that the object is the likely source of the radiation pressure responsible for creating the shape of the Cone Nebula.

The Cone Nebula resembles the better known Pillars of Creation, a star forming region made famous by the Hubble image in 1995, located in the Eagle Nebula (M16) in the constellation Serpens. Pillar structures like these, formed of cold gas, are common in large star forming regions and believed to be incubators for very young stars. The Cone Nebula was discovered by the German-British astronomer William Herschel on December 26, 1785, almost two years after he had discovered the Christmas Tree Cluster. Herschel catalogued the nebula as H V.27. Cone Nebula, the Christmas Tree Cluster and Hubble’s Variable Nebula.

The nearby NGC 2261, or Hubble’s Variable Nebula, probably lies behind the Cone. It is a bipolar nebula about 3 years across, illuminated by the variable star R Monocerotis. Its name comes from the fact that, like the central star, the nebula varies in brightness." -- from Constellation-Guide.com