NGC 6781 is a nice example of a planetary nebula. These nebulae are formed when a star begins reaching its end of life. The star begins throwing off shells of gas that expand away from the star. This forms a ring of hot ionized gas that we see as a planetary nebula.

In this photo, the bright bluish star at the center of the nebula is the star that created the planetary nebula. The nebula is about 2 arc minutes in apparent diameter - a little bit larger than its more famous cousin, the Ring Nebula.

In this image, North is Up. This image is cropped to 39% of the original full frame.

Exposure Details
Lens	Celestron C-8 SCT with Celestron focal reducer
Focal Length	1260mm
Focal Ratio	f/6.3
Mount	Schaefer GEM - 7 1/2
Guiding	80mm f/11 guidescope with PHD Guiding
Camera	Canon 20Da
Exposure	32 subexposures of 300 seconds each plus 61 exposures of 150 seconds at ISO 1600 - about 5 1/4 hours total exposure
Calibration	30 darks, 30 flats, 30 bias
Date	September 26 and 27, 2011
Temperature	58F on 9/26, 61F on 9/27
SQM Reading
Seeing	3 of 5 on 9/26, 4 of 5 on 9/27
Location	Pine Mountain Club, California
Software Used	Images Plus 4.0 for camera control, calibration, stacking and digital development. Photoshop CS5 used for flat fielding, curves, color correction, saturation adjustments, star shrinking, and high pass filter. HLVG for additional color correction, Carboni Actions for additional saturation adjustments.
Notes	This is a nice planetary which is not too commonly photographed. I'm fairly pleased with the final result.