About this Image
The famous bicolored nebula M20 situated in Sagittarius is famous for its three-lobed appearance. The dark dust bands that cause this effct are cataloged as Barnard 85.
The red emission nebula with its young star cluster near its center is surrounded by a blue reflection nebula which is particularly conspicuous to the northern end.
20 " Keller cassegrain in corrected secondary focus at f/9
|Camera||SBIG STL-11000M at -20C, 8-pos STL filter wheel|
|Filters||Baader RGB, H-alpha, (7 nm)|
|Date||May 04, 2008.|
|Sky Conditions||dark skies, raw FWHM 1.3-1.6" temperature 10 C,|
R:G:B = 30:30:40 minutes (10-minute sub-exposures); synthetic luminance used;
Ha: 30 min single exposure for center crop;
Maxim DL 4.5;