The Ring Nebula in Lyra is a planetary nebula around 400 light-years away. It has a glowing “shell” of ionized gas, which is a sign that the nebula was formed from the dying remains of a star that was once very much like our own sun. The Ring Nebula is fairly small in an astronomical sense, around a light-year across. Yet it is still a large object, being around 500 times the diameter of our solar system. It was the second planetary nebula to be discovered, by Antoine Darquier de Pellepoix in January of 1779. For many years the faint star visible in the center of the ring was unknown. However, in 1800 the German astronomer Friedrich von Hahn discovered it to be a white dwarf star around the size of a planet.
In the image, the large amounts of gas can be seen in the light blue and white rings. The central white dwarf star of the nebula is very faint, barely visible, but outside stars are left in the picture so that the brightness can be compared to other bright objects in the sky. To observers without a camera, it is usually a white object, while in this image, traces of blue and green can be seen. If there ever is color visible, it is usually a slight green shade since the Ring Nebula has green emission lines.
"Ring Nebula." redOrbit Reference Library. Accessed 6 December 2010. <http://www.redorbit.com/education/reference_library/stellar_bodies/ring_nebula/63/index.html>.
Nemiroff, Robert and Jerry Bonnell. "M57: The Ring Nebula" Astronomy Picture of the Day. 2009 November 15. Accessed 6 December 2010. <http://antwrp.gsfc.nasa.gov/apod/ap091115.html>
|Right Ascension (J2000)||18:53:35|
|Filters used||blue(B), green(V), red(R), and clear(C)|
|Exposure time per filter||
60 seconds in C,V,R
300 seconds in B
October 26, 2010