The Pinwheel Galaxy (also known as Messier 101 or NGC 5457) is a face-on spiral galaxy located in the constellation Ursa Major at a distance of about 25 million light years.  It was first discovered by Pierre Méchain on March 27, 1781, and communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final entries.

http://en.wikipedia.org/wiki/Pinwheel_Galaxy

 

ABOUT THE IMAGE

DATE/TIME:  The evening of April 5th, 2011.

CAMERA:  Canon XSI, 450Dm

TELESCOPE:  Orion 100mm ED refractor @ F/9

ISO SETTING:  800

EXPOSURES:  27

EXPOSURE LENGTH:  400sec.

TOTAL EXPOSURE LENGTH:  3hrs.

SUBTRACTIONS:  10 darkframes, 10 bias frames

CAPTURE SOFTWARE:  MaximDL

STACKING SOFTWARE:  Deep Sky Stacker

PROCESSING:  Photoshop CS3