Canon XSi, modded, Total RGB 70 min. = 14x5 min, ISO 1600
Baader MPCC, Bresser PN 8" OTA at F4, EQ6 mount, guided w/PHD and EQMOD
The Rosette Nebula is a large, circular H II region. Located near one end of a giant molecular cloud the nebula lies 4700 light years away from Earth, in the near side of the Perseus Arm.
The nebula measures roughly 130 light years in diameter, and its mass is estimated to be around 10,000 solar masses. It extends over an area of more than 1 degree of sky across, or about 5 times the area covered by the full moon.
Star formation is still in progress in this vast cloud of interstellar matter; a recent finding of a very young star with a Herbig-Haro type jet by astronomers at the NOAO has been announced in January 2004. Dust lanes of huge proportions are clearly visible in this image (and a zoom-in image is available if you press "next"). The radiation from the young stars excite the atoms in the nebula, causing them to emit radiation, thus producing the emission nebula we see.
The only star cluster which is definitely associated with the Rosette nebula is NGC 2244 at the centre of the nebula, the stars of which having been formed from the nebula's matter. This cluster was discovered by William Herschel in 1784. NGC 2252 at the northwest of the nebula may also be part of the nebula, although it has an unknown distance.
A survey of the nebula with the Chandra X-ray Observatory in 2001 has revealed the presence of very hot, young stars at the core of the nebula. These stars have heated the surrounding gas to a temperature in the order of 6 million kelvins causing them to emit copious amounts of X-rays.
The information above was compiled from: http://messier.obspm.fr/xtra/ngc/n2244.html, http://en.wikipedia.org/wiki/Rosette_Nebula, and http://www.atlasoftheuniverse.com/nebulae/ngc2237.html.