M101 is another spiral galaxy in Ursa Major but because it is presented face on it is rather faint and difficult to see in binoculars unless you have a very dark sky. Overall, the spiral arms cover an area almost the size of a full moon. However, in small telescopes only the central core will be visible.
27 million light years away, it’s discovery is credited to Pierre Méchain in 1871 and it’s spiral structure was first described by Lord Rosse in the 19th century using his 72″ reflector. It’s diameter of 170,000 light years is about twice the size of our own Milky Way galaxy. An unusual feature of this galaxy is the large number of star forming areas in the spiral arms. Some of these can be seen in this image as small bright regions with the characteristic blue tint of hot young stars.
Ongoing problems with tracking limited the maximum sub-exposure times to 120 seconds and a lot of these still had trailed stars leaving me with a stack of 16. As a result, the final image is rather noisy.
