The Ring Nebula (Messier 57) is a planetary nebula in the constellation Lyra approximately 2300 Ly from earh. Planetary nebula are formed when ionized gas is expelled by a red giant star, which was passing through the last stage in its evolution before becoming a white dwarf.
Taken in narrowband using the California, France, Hawaii Telescope palette
(Hα = Red, OIII = Green, SII= Blue)
Unfortunately my OIII data was slightly out of focus the the results is not a good as it could be. If you want to know more the asttobin link is: http://www.astrobin.com/255438/