Abell 21 is a planetary nebula in the Gemini constellation. It is commonly known as Medusa Nebula.
Image taken using the Schulman Foundation’s 24-inch telescope on Mt. Lemmon, AZ, using SBIG STL-11000M camera. Data frames by Adam Block. LLRGB processing using Maxim DL, CCDSharp, and Photoshop CS2 by JDS.
Click for larger view and more details (including purchasing options).
