M45 - The Pleiades
Technical details.
Taken with a 200mm Canon lens on a 20Da, 20 exposures each of 30s at iso 800. Stacked using ImagesPlus and processed in Photoshop.
Taken in September 2007 at the Kelling Heath star party, Norfolk, UK.

M45 The Pleiades or Seven Sisters
This brilliant 1st magnitude open star cluster is visible in the constellation of Taurus. The blue nebulosity is due to reflected light on a dust cloud passing in front.