NGC 6781 - Planetary Nebula in Aquila
NGC 6781 - Planetary Nebula in Aquila
NGC 6781 - Planetary Nebula in Aquila
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.