by Rod Pommier
Telescope/Mount: Celestron Compustar C14. Camera: SBIG STL 11000M with Baader Planetarium LRGB filters.
SBIG AO-L Adaptive Optics at 7Hz. Location: Pommier Observatory, Portland, OR, USA. Dates: 2013-08-17 and 2013-08-18. Exposures: LRBG=100:100:100:100.
M15 is a globular cluster located in a star-poor field off the tip of Pegasus' nose (the star Enif). It lies 33,600 light-years from Earth. It is a Shapley-Sawyer class IV globular cluster, which are characterized by globulars that have considerable scattering of peripheral stars, but their hallmark is that they still retain a small dense core of stars that cannot be resolved. In the case of M15, the dense core is intensely bright, and has distinctly triangular shape outlined by dark lanes, one of which is remarkably linear.