Jim Burnell's CCD Images - M21
 
M21
Object: M21 (NGC6531)
Open Cluster
 Const.: Sagittarius
Camera: HX916 Scope: AP130 Mount: AP1200GTO
Filter(s): IR block Exposure: 12x20s blank
The open cluster M21 in Sagittarius. A stack of 12 twenty second exposures using a 5" f/6 refractor. The image was calibrated, defect corrected and stacked using AIP4WIN.