The Rosette Nebula in Hydrogen Alpha + RGB
Rosette Nebula

The Rosette Nebula [click on the image to see it 2x]

Click HERE to see the pure Hydrogen Alpha channel

---------------------------------------------------------- From SEDS.ORG

The Rosetta Nebula is a vast cloud of dust and gas, extending over an area of more than 1 degree across, or about 5 times the area covered by the full moon. Within the nebula, open star cluster NGC 2244 is situated, consisted of the young stars which recently formed from the nebula's material, and the brightest of which make the nebula shine by exciting its atoms to emit radiation. Star formation is still in progress in this vast cloud of interstellar matter.

Although various values for its distance occur in the literature, our adopted distance from the Sky Catalog 2000 implies a true diameter of the nebula of about 130 light years.

Open cluster NGC 2244 was discovered by Flamsteed about 1690.

Camera: Apogee U16M 
Filter(s): Astrodon Gen II H-Alpha (5nm) and RGB
Scope: AP155 F7 w 4" FF
Exposure: 7 x 15 minutes h-alpha, 4x10 min each of RGB
Flesherton, Ontario, Canada
Feb 20, 2011 (h-alpha) Mar 27, 2011 (RGB)
Ambient temp -10C; camera temp -35C; Moon just past full for h-alpha; no moon for RGB
Images captured using CCDSoft5
Images calibrated (darks and flats), aligned and sigma-reject combined in Maxim
Contrast / Brightness adjustments, Levels, Russ Croman's GradX in Photoshop CS4