The famous interacting spiral galaxy Messier 51 (NGC 5194) in the constellation of Canes Venatici with its small companion galaxy NGC 5195 on May 26, 2012. The galaxy pair is about 23 million light years from Earth and was discovered by Charles Messier in 1773. The smaller galaxy NGC 5195 was discovered in 1781 by Pierre Méchain.

Nineteen 3 minute exposures at ISO 800 with in-camera dark frame subtraction were stacked with Deep Sky Stacker and further processed in Photoshop.
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.