Astral Imaging at Dogwood Ridge Observatory

Latitude: 3748'51.0" N"
Scottsville, Virginia 24590


(click on thumbnails to go to that image's page)






NGC 2237, 2238, 2239, and 2246 - The Rosette Nebulae
The Wide Field Image in Monoceros

Image Information

Quoted from

Discovered by John Flamsteed about 1690.

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. Its parts have been assigned different NGC numbers: 2237, 2238, 2239, and 2246. 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; a recent finding of a very young star with a Herbig-Haro type jet by astronomers at the NOAO has been announced in Press Release NOAO 04-03 on January 22, 2004.

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. Burnham quotes a mass estimation of 10,000 (Minkowski 1949) to 11,000 (Menon 1962) solar masses, so it is one of the more massive diffuse nebulae.

Open cluster NGC 2244 was discovered by Flamsteed about 1690. The nebula, however, was not even seen by William Herschel (who found the cluster); its different parts were discovered only by John Herschel (NGC 2239 = GC 1420 = h 392), Marth (NGC 2238 = GC 5361 = Marth 99), and Swift (NGCs 2237 and 2246); note that while now these numbers are used for describing parts of the diffuse nebula, their original NGC description is quite different:

2237  pretty bright, very very large, diffuse (?= [GC] 5361 [= NGC 2238])
2238  small [faint] star in nebulosity
2239  star of mag 8 in large, poor, bright cluster
2246  extremely faint, large, irregularly round, extremely difficult
Nevertheless, the nebula is a splendid object, especially for astrophotography.


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This RGB image consists of images all taken at -30C at bin 1x1 for 10 minutes each. A total of 18 red, 18 green, and 18 blue images were used. All images used totaled 9 hours. All data was acquired using MaxImDl/CCD version 5.23 using ACP.   Images were reduced and saved in Pix Insight version 1.7.  Alignment, average combining, along with histogram stretching, deconvolution, and HDRWavelets was done using Pix Insight. Photoshop CS 5 was used to create the JPG versions for web presentation.  The image data was collected January 7-22, 2013 using ACP version 6.2.

The Ha image consists of 12 - 30 minutes subs taken at bin 1x1 and -30C. A total of 6 hours of data. Same software as above.

The third image is a HaRGB combination done using all the above data and a script for combining the data to render the HaRGB image with natural star colors. Total data time is 15 hours.

Equipment and Location Information

Date January 7-22, 2013
Location Dogwood Ridge Observatory
Optics Takahashi FSQ-106
Mount Astro Physics AP1200GTO
Camera SBIG STL-11000M/FW10/
Filters Baader LRGB 50.8mm
Conditions Temperature low to mid 30s with moderate to good  seeing. Transparency good to moderate.

  Last Modified :01/23/09 12:40 AM