The Pinwheel Galaxy is a spiral galaxy located in the constellation Ursa Major.
This image was taken over two successive nights. Because of where I was located I could leave my gear set up during the day. This ensured that the polar alignment and the other usual variables did not change between sessions. The bad news is that this was done in mid-May and was interrupted by aurora so even with two nights of imaging, I still only ended up with a little over two hours of usable image frames.
Fortunately M101 is pretty bright and has easily detectable structure. Another plus is the spiral arms are fairly bright in relation to the core. This makes it fairly easy to adjust the final image so that even with only two hours of exposure, both the core and arms still show up against a nice black background.