The Rosette Nebula in Monoceros is a stellar nursery, where new stars are born from the gas and dust of the nebula. The cluster NGC 2244, at the centre of the image, consists of stars only a few million years old, but their powerful stellar winds have cleared the central region of the nebula, a cavity estimated to be about 50 light-years across. The nebula is about 130 light-years across and is about 5200 light-years from Earth. It is catalogued with several entries in the New General Catalogue (NGC), published in 1888. This demonstrates that the optical observations on which the catalogue was based were unable to reveal the full structure of this nebula, which is almost 3 times the diameter of the full moon in the sky.

Note on colours:

This image has been taken with narrow-band filters, each sensitive only to the bright emission of a particular element (where H is the symbol for hydrogen, O for oxygen and S for sulphur). The images have then been assigned to the red (S), green (H) and blue (O) channels of the final image. Such “SHO” images are therefore false colour. If our eyes were sufficiently sensitive, we would see it as predominantly red, due to the strong emissions from the Hydrogen gas clouds.