The Rosette Nebula (NGC 2237-9) in H-alpha

Posted by CraigAndTammy
on Wednesday, February 23, 2011

The Rosette Nebula (NGC 2237, Caldwell 49, Sh2-275) is a large HII star-forming region that lies just east of Orion in the constellation Monoceros. This large molecular cloud is comprised of several smaller parts which were discovered by three different astronomers: John Herschel (NGC 2239), Albert Marth (NGC 2238) and Lewis Swift (NGC 2237 & 2246). In 1690, John Flamsteed discovered the Rosette's central open cluster, NGC 2244. From Earth, the nebula is approximately 5000 light years distant and appears to be about 1 degree across - roughly 5 times the size of the full Moon. At an apparent magnitude of 9.0, the nebula is impossible to see with the unaided eye making it's discovery difficult.

Telescope: William Optics ZenithStar 66
Accessories: William Optics 0.8x FR/FF vII; Dew control by Dew Buster
Mount: Orion Atlas EQ-G (hyper-tuned by Astrotroniks) controlled by EQMOD
Guiding: TS-OAG9 Off-axis, using a Starlight Xpress Lodestar via PHD
Camera: Atik 314L+ monochrome CCD @ -10.0C with Atik EFW2
Filters: Baader 7nm H-alpha
Exposure: 40 x 10min. (6hr. 40min.)
Acquisition: Images Plus Camera Control v4.0b
Processing: Bias calibration in Images Plus v3.80; bad pixel map in Nebulosity 2.3.6c; Registration and combine in RegiStar
Post-processing: Adobe Photoshop CS4; Carboni’s Tools
Temperature: N1:56.1F – 52.1F; N2:49.8F – 41.9F
Date(s): February 13 & 14, 2011
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