Abell-21, The Medusa Nebula

Type: Old Planetary

The Medusa Nebula, a substantial planetary nebula, spans approximately one-third of the diameter of a full moon. Initially identified by George O. Abell during the 1950s, it was cataloged as the 21st item in his list. Its name, "Medusa," stems from its resemblance to a jellyfish, characterized by intricate, sinuous filaments. Interestingly, the nebula's spectrum exhibits a relatively subdued emission in O-III compared to the norm, as H-alpha appears roughly twice as intense.