Messier 101 - the Pinwheel Galaxy. A grand-design spiral galaxy that's estimated to be approximately 21 million light years away and 170,000 light years across, compared to the Milky Way's 250,000 light year diameter, it's estimated to be home to around one trillion stars - more than double the Milky Way. Its asymmetrical shape is due to gravitational forces from surrounding smaller galaxies, one of which is visible in the upper right of the frame, a smaller elliptical galaxy, NGC 5204. This shot is just about ten hours (118 x 300s) of total exposure taken with a ZWO ASI294MC-Pro through an Explore Scientific ED127CF at 952mm focal length.