M20 is known as the Trifid Nebula, although it clearly has 4 lobes not 3. M21 is the star cluster to the upper right of the nebula. These two objects look to be related, but the cluster is approximately 1,000 light years closer to Earth, at 4,100 light years the Nebula is approximatly 5,000 light years distant. These two objects can be found in the summer sky in the constellation Sagittarius.

This photo is a reprocessing using the new version 2.2 of AIP4WIN to stack and calibrate the raw images from my Canon 10D camera. I'd been using version 2.1 and was unable to satisfacterly process the RAW impages, I needed to convert to TIFFs. I'm finding that I get much less noise and seamingly a much higher signal to noise ratio.

Details:
Taken July 14, 2007
Telescope: William Optics 80mm Fluorite Doublet APO
Camera: Canon 10D, unmodified
Mount: Celestron CGE
1.5 hours total exposure; 30 x 180 seconds. Unguided. ISO800.
Calibrated with Dark and Flats subtracted in AIP4WIN
Post processing in PixInsight LE, Photoshop Elements 3.0, and AIP4WIN