Globular cluster M15

62 minutes exposure on T24 telescope from iTelescope.net (61cm aperture).
50 minutes for luminosity, and 4 minutes each for RGB with 2x2 binning. Apparently, color shots needed more time to lower noise.

The brightest starts in the cluster have magnitude of 12.6, and that super-bright star at the top-right part of the photo has magnitude 7.6 (which is twice weaker than we can see with our eye in perfect conditions). There are more than 100'000 stars in this cluster.