Messier 101, also known as the Pinwheel Galaxy (NGC 5457) is a face-on spiral galaxy that can be found in the constellation Ursa Major at 21 million light years from Earth.
With a diameter of approximately 170.000 light years, this galaxy is almost twice as large as our own Milky Way.

This galaxy features some huge and extremely bright H II regions in which stars are being formed, these can be seen as “blobs of nebulae” in the image.
A supernova was discovered on August 24, 2011 being the 4th supernova recorded in M101.

M101 is the brightest galaxy of a small group which consists of approx. 9 galaxies, named the M101 Group.
It is however not an easy visual target as it has a rather low surface brightness.