The Ring Nebula in Lyra, also known as M57 or NGC 6720 is the most famous example of a planetary nebula. Located at 0.7 kpc (2300 light-years) from us, the nebula is illuminated by a white dwarf of 15.8 visual magnitude.
See also:
- Messier 57 (http://www.seds.org/messier/m/m057.html), SEDS Messier pages