Medusa Nebula
The Medusa Nebula, also known as Abell 21 or Sharpless 2-274, is a planetary nebula situated in the constellation Gemini. It’s a fascinating object because, despite its name, it doesn’t have the classic ring-like shape typically associated with planetary nebulae. Instead, the complex filamentary structures that give the nebula its ‘Medusa-like’ appearance are remnants of a low-mass star that shed its outer layers, similar to how mythological Medusa’s hair was said to be a mass of serpents. The radiant colors you see are from the glowing ionized gas, primarily hydrogen and oxygen, energized by the ultraviolet radiation from the dying star at its core.
Capturing the enigmatic beauty of the Medusa Nebula, or Abell 21, required a series of meticulously planned astrophotography sessions. Over several nights in March 2023, a total of 46 frames at 5 minutes each were acquired, accumulating to 3 hours and 50 minutes of exposure time. Utilizing a HaOiii filter, which isolates specific wavelengths of light emitted by hydrogen and oxygen, helped to enhance the nebula’s features and bring out the delicate structures against the stark backdrop of space. The use of a ZWO 533i MC color camera, attached to the steadfast Sky-Watcher 120ED Evostar telescope on an HEQ-5 mount, and guided with precision by a ZWO 290MM camera, ensured that each frame captured the faint glow of this distant nebula with clarity and depth, creating a striking portrait of this cosmic phenomenon.