Instrument

Celestron C11 @  ~f/10.48 (2930 mm fl) 1.265 arcsec / pixel. 

Mount

Paramount ME

Camera

SBIG STL-11000 w/ internal filter wheel, AstroDon Filters

Acquisition Data

12/26/2007 & 2/15/2008  Chino Valley... with CCDAutoPilot3

Exposure

H-Alpha    210 min.  (7 x 30 bin 2x2)

Software

CCDSoft, Sigma-Clip, Photoshop CS w/ the Fits Liberator plugin, Paint Shop Pro,and Noel Carboni's actions

Comment

North is to the left.

At a distance of about 1500 light years, the Horsehead Nebula, in Orionis, is part of a large dark molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800's. The background glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left.

Source: NASA APOD