The Rosette Nebula (also known as Caldwell 49) is an HII region located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy. The open cluster NGC 2244 (Caldwell 50) is closely associated with the nebulosity, the stars of the cluster having been formed from the nebula's matter.
This particular iteration of the nebula was shot with a monochrome camera and Hydrogen Alpha, Oxygen III and Sulphur II filters, hence the differing colours from the other two images shot with a one shot colour camera.