Catalogued as IC 5146, the Cocoon nebula is located in the northern constellation Cygnus. It is located close to 4,000 light years away. The bright star close to the center of the nebula is likely only to be a few hundred thousand years old. The nebula is very small and often difficult to see without a large telescope.
Being a stellar nursery, each color describes a different type of nebula, such as a bright red emission nebula. Because the Cocoon nebula has a reddish hue, we can infer that it contains large amounts of hydrogen. When excited by ultraviolet light, the hydrogen gas radiates red-colored light. This primarily reddish hue, with a few hot bright blue stars, indicates that this nebula is still fairly young. This nebula also contains blue reflection nebulae. The blue color is coming from carbon dust grains reflecting light from nearby stars. Finally the Cocoon nebula contains dark absorption nebulae which are due to interstellar dust clouds that block the light from being seen. The image above is approximately 22 light years wide.
Crawford, K., Nemiroff, R., & Bonnell, j. (2008, August 27). IC 5146: The Cocoon Nebula. In Astronomy Picture of the Day. Retrieved December 6, 2010 http://apod.nasa.gov/apod/ap080827.html
Cannistra, S. (2004, September 5). Cocoon Nebula (IC 5146). In Starry Wonders. Retrieved December 6, 2010 http://www.starrywonders.com/cocoon.html
|Right Ascension (J2000)||21h 53m 24s|
|Declination (J2000)||+47 16' 00"|
|Filters used||blue(B), green(V), red(R), and clear(C)|
|Exposure time per filter||60 seconds in C, 300 seconds in BVR|