M101 – Pinwheel Galaxy

Full size image can be seen here : M101 with Canon 400D

M101 in Ursa Major
7 x 10 minute exposures (70 minutes)
Skywatcher 8″ Newt / Canon 400D
Romney Marsh (Dark sky site)

M101, also known as the Pinwheel Galaxy, is about 27 million light years away. With a diameter of 170,000 light years it is nearly twice the size of the Milky Way. It is thought that M101 underwent a near collision with another galaxy, and the associated gravitational tidal forces caused the asymmetry.