M51 is better known as the Whirlpool Galaxy.  It was the first galaxy found to have a  spiral form.  M51 was disconvered my Messier in 1773.  M51  is a Sc type spiral and it about 35million light years distant. NGC 5195  is the smaller inrregular galaxy to its north.  Some studies indicate the two are interacting with one another and other studies indicate the two lie on two different planes.  Either way this  pair is one of the most elegant in the sky.
This image is an average of (10) 5 min exposures for a total exposure time of 30min.  It was taken with a Starlightxpress MX7C attached to a Meade 8"LX200.  The image was aquired with Astroart and processed with AIP4WIN.