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Astr110 Photography Projects, Fall 2007

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Clown Face Nebula (NGC 2392), John Miller

Clown Face Nebula

The Clown Face Nebula, also known as the Eskimo Nebula (NGC 2392) is a planetary nebula. A planetary nebula is an shell of gas that is often complex, and is illuminated by a star that has run out of fuel to burn. It actually has nothing to do with planets other than its name, which was invented by William Herschel in the 1780s because they reminded him of Uranus. This particular nebula was in fact discovered by William Herschel in 1787. It is estimated to be at a distance of about 3000 light years, and is thought to be around ten thousand years old. It is found in the constellation Gemini, and can only be observed through a telescope due to its low brightness.

The center of this nebula is bright blue because of the blue star in its center. The blueness of the star means that it is extremely hot as stars are concerned. You can see three separate rings of green gas surrounding the star, and on the outermost ring, you can see a more reddish tint in the gas shell. The green gas is hydrogen, and the red band nitrogen. Scientists believe that the gases take this shape due to dense material around the star's equator preventing stellar winds from pushing the material. Its linear size is 1.4 light years.

References:
The Internet Encyclopedia of science
<http://www.daviddarling.info/encyclopedia/E/Eskimo_Nebula.html>.

Deep-Sky Companions: The Caldwell Objects, p. 154
<http://books.google.com/books?id=3Hg6YHgx9nAC>

Right Ascension (J2000) 07:29:12
Declination (J2000) 20:55:00
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 5x60 seconds in C, 300 seconds in BVR
Date observed

October 20, 2007 (C)
October 20, 2007 (BVR)