Messier 51 (Whirlpool Galaxy)
Messier object number 51 (NGC 5194) is a spiral galaxy and in the constellation of Hunting Dogs. It is also known as the Whirlpool Galaxy. It is approximately 20 million lightyears away from earth.
Whirlpool Galaxy (M51, NGC5194) is one of the most beautiful spiral galaxies in the night sky. It is interacting with its smaller companion NGC 5195, which is also easily observable in amateur telescopes. Several supernovae have been observed in the Wirlpool Galaxy, which is a great event to help determine the distance of the galaxy. It's diameter is estimated at 76,000 lightyears, which brings it at an overall size of 43% of our own Galaxy.