Sunday, April 30, 2006
Universe Today - Astrophoto: The Ring Nebula by Stefan Heutz: "Riding high in the northern sky near the bright white star Vega, the Ring Nebula is one of the most favorite deep sky objects targeted visually by backyard stargazers. It can be seen through telescopes with apertures as small as four inches. But larger telescopes can reveal the faint planet sized central star that created this night sky spectacle. The Ring Nebula was discovered about 200 years ago by French astronomer Charles Messier, an avid comet hunter, and made its way into his catalog used to keep track of false comets as item number 57.
Recent imagery by the Hubble Space Telescope has confirmed that the Ring Nebula is not spherical in shape; it is more like a tube that is slightly constricted in the middle so that it resembles a stretched hourglass. By chance alone, Earth is positioned so that we can look almost straight through from one end. Tubular shapes like this are common throughout the universe because thick disks of gas tend to expand outward very slowly leaving the material free to become extended perpendicularly. One of the other more spectacular examples of this shape is exhibited by the Little Dumbbell Nebula. It's located in the constellation of Perseus and is positioned so that we have a side view."The light we see left the Ring nebula 2000 years ago