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California Nebula

The California Nebula derives its name from its characteristic shape on long exposure photographs.  This gas cloud is located 2000 light years away in the constellation Perseus.  It has a total mass of 240 suns, and is illuminated by the bright star to its right in this photo.  Visually, this nebula is hard to observe even with large telescopes, because its dim light is spread over an area 4 times the size of the moon.  The image on the left was acquired in the light polluted skies of the northeast, using a Hydrogen-alpha narrowband filter for luminance, with an ST10-XME camera and a 300mm Nikon f4.5 lens.  Exposure times were 120 min H-alpha luminance, 15 min R, 20 min G, and 21 min B.  The pure H-alpha image is shown at the bottom of the page. For another comparison, I captured the photograph below with a Pentax 300mm f4.5 telephoto lens, Kodak 1000 speed professional film, and a 20 minute exposure in the clear skies of Cloudcroft New Mexico.

Music:  California Dreamin'