Object of the Season (Winter 2016)

Planetary Nebula Abell 21 in Gemini

This interactive image of Abell 21 was provided by the Digitised Sky Survey using Aladin Sky Atlas.

This is the famous “Medusa Nebula” – a real challenge for visual observers (use an OIII filter). The large planetary nebula is located at the border of Gemini and Canis Minor. George Abell discovered the object in 1955. It is an old example of its class. The central star (WD 0726+133) is a faint blue object.

Results of the observations of Abell 21 will be published in DSO 176.

Abell 21
Position (2000)
07 29 02.7 +13 14 48.0 (Gem)
Planetary Nebula
12' (4 ly)
1,500 ly
Other Designations
PK 205+14.1, Sh 2-274, YM 29, ARO 388

Wolfgang Steinicke - Nebulae and Clusters Section Director