This is the finest example of a planetary nebula. This type of object
gets its name not because it has anything to do with planets, but
because astronomers using early telescopes noticed their round shape,
and thought they looked like planets. M 27 is actually 1200 light years
away, far outside our solar system. Planetary nebula form when a star
blows off its outer layers of gas in an expanding bubble. The now-smaller
star which remains at its center causes those gasses to glow. M 27 probably
began with its stellar explosion 3,000 to 4,000 years ago.

Image data:
Camera: Canon 350 XT (modified)
Exposure: ISO 800, 5 minutes x 26 (through light clouds / haze)
Telescope: 10" Schmidt-Newtonian, Baader MPCC (unguided)