At the middle of the Rosette Nebula is the young (4 million
years) open star cluster NGC 2244, whose intense radiation is clearing
out the middle part of the nebula and is setting the rest of it aglow.
Though the star cluster is visible to the unaided eye, the nebula is
very difficult to see visually even with a telescope because it is both
dim and spead out (its diameter in the sky is twice that of the full moon).
Throughout the nebula one can see dark lanes of dust and black "Bok
Globules," condensing dust and gas in the first stages of new star
formation. The Rosette Nebula is seen in the constellation Monoceros,
just to the East of Orion. It is about 5000 light years away, and
130 light years in diameter. This image is taken through a hydrogen-
alpha filter, which allows only the narrow band of light emitted by
such a nebula to pass through, and thus showing more of the nebula's fine
structure.

Image data:
Camera: SBIG ST-4000XCM
Exposure: 270 minutes (15 minutes x 18)
Telescope: 10" Schmidt-Newtonian, Baader MPCC