The globular cluster Messier 13 in the constellation Hercules on June 15/16, 2012. Discovered by the English astronomer Edmond Halley in 1714, this cluster contains an estimated 300'000 stars and is 25'100 light years from Earth. The cluster which measures 145 light years in diameter can be seen in a small telescope.

Eighteen 3 minute exposures at ISO 800 and 22 separate dark frames (with the same settings) were added in DeepSkyStacker for this shot. The mild temperatures caused a considerable amount of noise in the image.
Equipment: Canon EOS 20Da camera, TeleVue coma corrector, Zambuto 16" f/5 quartz optics in a Dieter Martini dobsonian telescope, dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Teleskop-Service off axis system TS-OAG9 EOS.