The Blue Snowball Nebula is a planetary nebula located in the constellation Andromeda. It was discovered by Herschel in 1784.

The variable central star (its magnitude varies between 12th to 16th) is a bluish dwarf with a continuous spectrum and a temperature of about 75,000 Kelvin, which makes it one of the hottest stars known; it isn't seen in this image, which required a resoltion beyond what the seeing could deliver that night.

The nebula's distance is about 5,600 light years, and it's actual size is about 0.8 light years (i.e. nearly 50,000 Astronomical Units).