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Catalogue and alternative designations M15
Type Globular Cluster 
Position  21 29 58, +12 10 01
Constellation Pegasus
Camera and Telescope STXL16200 and 36.8cm Ritchey Chretien
Focal Ratio F9
Exposure Details LRGB exposure with Astrodon series 2 filters.  Luminance = 50 minutes (unbinned) , Red = Green = Blue = 35 minutes (binned 2x2)

M15 is one of the best globulars in the northern sky. It was discovered by Maraldi in 1746 and included in Messier's catalogue in 1764.  At 12 billion years it's one of the oldest known globulars and is a very easy visual target at magnitude 6.2 and 18' in diameter.  M15 is also one of the small number of globulars to contain a planetary nebula (Pease 1).  Pease 1 is very difficult to see.  It's located just to the top of the bright centre in this image.