The Rosette Nebula is a collection of emission and dark nebulae in the constellation Monoceros.
This area is a region of active star birth centered on the open cluster NGC
2239, the brighter stars in the core of the nebula. These stars formed
from the dust and gas of the nebula and their radiating pressures have blown a
massive bubble in the core region of the nebula about thirty light years
Eventually the stellar pressures of these stars and others that will form
will cause the nebula to dissipate.
These young and massive O type stars are the energy source for
the emission nebulosity and their pressure continues to form Bok Globules
within the nebula. Bok globules are denser clumps of dust and gas from which
protostars are formed. They are revealed as dark knots and pillars in
In total, this nebula spans about a degree of our sky or two full moon
widths and is about 5,500 light years distant. This means the roughly
spherical nebula is about 130 light years in diameter.
At magnitude 4.8, NGC 2239 is an open cluster visible to the naked eye and
makes for a fine visual target in both binoculars and telescopes.
However the nebulosity of the Rosette is much more difficult to see visually
with only separate portions of the brighter areas being visible (see
annotations). In point of fact, the Rosette Nebula region contains NGC
2237 through NGC 2239, NGC 2246 and open cluster NGC 2252 just east.
In addition, other HII regions have been cataloged as shown. It's also
cataloged as Caldwell 49 (the nebula itself) and Caldwell 50 (the central
American Horse Lake
Telescope: Orion 80ED @ f/4.7
Camera: Hutech Type I,
Exposure Count: 4 @ 2 min, 11 @ 4 min
Guiding: SBIG ST-402ME, LX200GPS
Acquisition and Focus: DSLR Focus
Images Plus - Calibration, Align/Combine, Digital
Neat Image - Noise Reduction
Photoshop - Levels Adjustment