The Medusa Nebula is a planetary nebula in the constellation of Gemini. It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by University of California, Los Angeles astronomer George O. Abell, who classified it as an old planetary nebula. 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. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported. The central star of the planetary nebula is a PG 1159 star.
Located nearby (top-right) is an Open Cluster, NGC 2395. It is poorly populated, making it difficult to locate. It contains approximately 30 members.

Telescope: Planewave Delta Rho 350 f3.0
Mount: Astro Physics 3600GTO “El Capitan”
Camera: ZWO ASI461MM pro / EFW-7
Guider: ZWO OAG-L-68 / ZWO ASI174mm Mini
Filters: Astrodon II 50mm Sq LRGB

L: 101×5 mins = 505 mins, R: 60×5 mins = 300 mins, G: 51×5 mins = 255 mins, B: 60×5 mins = 300 mins

Total Imaging Time: 22h 40m

Data Imaged remotely on 6 nights during December, 2025.
Data acquisition & Processing by David Churchill.

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