The Medusa Nebula is a large planetary nebula in the constellation of Gemini on the Canis Minor border. It also known as Abell 21 and Sharpless 274. It was originally discovered in 1955 by UCLA astronomer George O. Abell, who classified it as an old planetary nebula.[4] The braided serpentine filaments of glowing gas suggests the serpent hair of Medusa found in ancient Greek mythology.

Until the early 1970s, the Medusa was thought to be a supernova remnant. With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula.[4]

As the nebula is so big, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported. Because of this most websites recommend at least an 8-inch (200 mm) telescope with an [O III] filter to find this object although probably possible to image with smaller apertures. Wikipedia

This was my first go with the SBIG off axis guider "OAG" and the STi guide camera, mine is the color version. I set up in my driveway which shuffers from significant light pollution from a regional mall 1 mile south. I usually polar align with a polar scope, but I could only see polaris, so I used key pad routines. This took me over 1 hour, I hadn't done this for over a year and mistakes were made. The OAG/guide camera worked a charm.

Since I had both light polution and the moon when I started I decided to stick with the H-alpha filter for the entire time. I had to stop at about 3am as the target was nearing the tree line. More time is always better, but this came out pretty well.

Photo Details:
Taken on January 18 through 19th, 2013
Camera: SBIG ST-8300M
Exposures: 10 x 900 seconds Total 135 minutes
Filter: Baader Ha 7nm
Telescope: William Optics FLT110 @ f7
Mount: Astro-Physics Mach 1 GTO
Guided: SBIG AOG with SBIG STi color guide camera
Processing: CCDStack, PhotoShop CS6