Monday, July 30, 2012

M13 - Hercules Globular Cluster

M13 Hercules Globular Cluster
VAO, Webster NY
FWHM 2.2", 1x1 bin, 0.54 "/pix
12" Meade SCT
© Billy Vazquez
M13, the Hercules Globular Cluster was discovered by Edmund Halley in 1714 and catalogued by Charles Messier on 1764.   This cluster at an apparent magnitude of 6 contains about a million stars on an approximate sphere spanning 150 light years.  The image is a composite of  5x1 minute exposures unguided at f/6 on the VAO's 12" Meade to test the new Paramount MX mount.  Close inspection of the stars show a small drift of about 2 arc seconds per minute.  This is likely due to a non accurate PEC correction.  Still nothing to be sniffed at a plate scale of 0.54"/pixel.  The seeing was transparent and steady on July 29th, 2012 the reported FWHM was 2.2"