NGC 6946, also designated ARP 29, and commonly called "The Fireworks Galaxy," is an intermediate spiral galaxy.  It lies on the border of the constellations Cepheus and Cygnus, at a distance of about 10 million light-years from Earth.  It was discovered by William Herschel on September 9th, 1798.  It get's it's common nick-name "Fireworks Galaxy," from the multitude of star forming regions located within it's spiral arms.  

Also note in this image, the open cluster NGC 6939 (top left.)

http://en.wikipedia.org/wiki/NGC_6946

 

ABOUT THE IMAGE

 

DATE/TIME:  The evening of July 11th and morning of the 12th, 2013.

CAMERA:  Canon XSI, 450Da

TELESCOPE:  Celestron C9.25 SCT @ F/6.3

ISO SETTING:  800

EXPOSURES:  43

EXPOSURE LENGTH:  400sec.

TOTAL EXPOSURE LENGTH:  4hrs., 13min., 20sec.

SUBTRACTIONS:  16 dark frames, 40 flat frames, 16 dark flat frames.

CAPTURE SOFTWARE:  MaximDL

STACKING SOFTWARE:  Deep Sky Stacker

PROCESSING:  Photoshop CS3