NGC 2237 Rosette Nebula in Ha

The Rosette Nebula is a large, circular H II region located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy. The open cluster NGC 2244 is closely associated with the nebulosity, the stars of the cluster having been formed from the nebula's matter.

The complex has the following NGC designations:

NGC 2237 - Part of the nebulous region (Usually used to denote whole nebula)
NGC 2238 - Part of the nebulous region
NGC 2239 - Part of the nebulous region (Discovered by John Herschel)
NGC 2244 - The open cluster within the nebula (Discovered by John Flamsteed in 1690)
NGC 2246 - Part of the nebulous region
The cluster and nebula lie at a distance of some 5,200 light years from Earth (although estimates of the distance vary considerably) and measure roughly 130 light years in diameter. The radiation from the young stars excite the atoms in the nebula, causing them to emit radiation themselves producing the emission nebula we see. The mass of the nebula is estimated to be around 10,000 solar masses.

Telescope: Skywatcher ED80
Mount: HEQ5 Pro
Camera: QHY8
Filter: Baader Ha 7nm
Guidescope: Skywatcher 70/500mm
Guide with LVI SmartGuider
Exp. Time: 5* 20 minutes (bin 2x2) in Ha
Capture: Nebulosity 2.2.5
Stack: Deep Sky Stacker
Processing: Photoshop CS3

NGC 2237 Rosette Nebula Wiki