M57 - The Ring Nebula
The Ring Nebula, resembling its namesake, is a ring of material left over from the nova created during the death of a star. What remains of the star is merely a white dwarf star at the center (and visible) of the ring. The other bright star in the center of the ring is merely a foreground star having nothing to do with the nebula. Originally the nebula was thought to be a sphere of material but careful study with both ground-based and Hubble telescope images shows it is more like a cylinder of material rather than a sphere. Also note the very outer faint shell of gas, likely blown off in advance of the explosion that led to the denser material and shed much of the star's mass. To the left of the Ring Nebula is a spiral galaxy that looks to be small compared the Ring, however it is probably about 100,000 times larger due to its extreme distance in the background. The Ring Nebula is a favorite among amateurs since it is relatively bright and very easy to find positioned between two bright stars in the constellation Lyra the harp. Below is a very over processed and colorless image intended to show the outer rings of this nebula. Note there are actually three rings, each fainter than the previous. The outside of the brightest ring is probably about one light year across.
Optics: RC Optical System 20" F/8.2 (4165.6 mm Focal Length) Date: August 2009
Camera: SBIG ST10XME with Adaptive Optics Location: Columbus, Texas
Exposure: LRGB = 400:60:60:80 minutes Imager: Kent E. Biggs