M71 - A Globular Cluster


M71 (NGC 6838) is a loose, low density,  globular cluster found in Sagitta (The Arrow).  Some early astronomers incorrectly labled it a dense open cluster. It turns out its fairly close (for a globular) at 13000 light years.  It shines at magnitude 8.3, and is 7.2' across.

This shot was taken at f/6.3 with the 12" LX200, AO7, and ST-8E CCD from my home dome in Monmouth Oregon on Sept. 7, 2001. 

Filter Exposure Count Binning
Luminance 38 min (sum of RGB data)
Red 10 min 5 x 2 min 1x1
Green 10 min 5 x 2 min 1x1
Blue 18 min 9 x 2 min 1x1

A synthesized luminance frame was built by adding all frames together, then applying DDP and a touch of sharpening.  The original RGB frames were then blurred a bit to smooth them. Photoshop was then used to merge the L and RGB color data.