by Rod Pommier
This is a close up view of the Ring Nebula cropped and enlarged from a full field image, which showed the Ring Nebula in the context of being a very small planetary nebula in a starry field of the summer Milky Way. This close up image shows some of the internal detail of the Ring Nebula, which is remarkable considering its apparent diameter is only 230 arc-seconds. The Ring Nebula is a bipolar planetary nebula, meaning it has two equatorial rings of material. We view the two equatorial rings slightly off-axis rather than face-on, which gives the Ring an oval appearance. The internal detail comes from rarified areas and bright emission nebula in one of the equatorial rings being superimposed on other rarified and/or bright emission nebula of the other ring. M57 lies 2,300 light-years from Earth. Images were 30-second sub-exposures calibrated with dark, bias, and flat field frames.
Telescope: Compustar C14 SCT at f/11. Camera: Canon 20D, unmodified. Location: Pommier Observatory, Portland, Oregon. Date/Time:7-04-2010 08:10 UT. Exposure:80 x 30 seconds = 40 minutes at ISO 800.