M51 - Whirlpool Galaxy
Technical details.
Taken through a VC200L Vixen telescope at prime focus (f = 1800mm, D = 200mm, f 9)
Camera used Canon 20Da 50 exposures each of 30s at iso 3200. Stacked using ImagesPlus and processed in Photoshop.
Taken in September 2007 at the Kelling Heath star party, Norfolk, UK.
Published in  January 2008.

M51
This magnificant galaxy is actually in constellation Canes Venatici but is close to the handle of the big dipper. It is 15 million light years away. It is about 50,000 light years across and contains about 10 billion stars.