M71 – Loose Globular Cluster in Sagitta
 

Messier 71 (M71, NGC 6838) is a loose globular cluster in the constellation Sagitta. Its star distribution is very loose, but the cluster is much more rich and condensed than typical open clusters. M71 is about 25 light-years in diameter, and lies approximately 12,000 light years distant.

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M71 globular star cluster


Equipment
 TMB-130SS APO refractor at f/7 on a Losmandy G-11 equatorial mount
SBIG ST-8XM camera
SBIG CFW-10 filter wheel with Astrodon filters
Guiding: 60mm f/5 refractor and ST-402 camera
Imaging and autoguiding with MaxIm DL 4.57
Exposure
Luminance   30 minutes (30 x 1 min.), unbinned, -20°C
Red   30 minutes (30 x 1 min.) binned 2x2, -20°C
Green   30 minutes (30 x 1 min.) binned 2x2, -20°C
Blue   30 minutes (30 x 1 min.) binned 2x2, -20°C
Processing Dark and flat-frame processing in CCDStack
Statistical-combined in CCDStack
Levels, curves, color-combine in Photoshop CS3
Date and Location 10 October 2007
Montpelier, VA    N 37° 49' 12", W 77° 42' 06"