Horsehead Nebula

The Horsehead Nebula also known as Barnard 33 is a dark nebula in the constellation Orion and it is located just south of Alnitak.  This dark nebula is located about 1500 light years away from Earth. The red glow is imparted by ionized hydrogen from nearby star Sigma Orionis.

The image shown was taken at VAO with broadband Johnson BVR filters.  Total exposure time is 55 minutes ( 4x300s on B and V, 3x300s on R filters).   It was further processed in PixInsight for dark subtraction and flat field division.  A median noise reduction algorithm was used with a 3x3 kernel to eliminate most of the chrominance noise.   The telescope used was the 12" inch SCT at f/6.3.   Guiding was done with Metaguide with an 80mm APO refractor and Lumenera Skynix. 

In addition I present to you the unedited out of the telescope combined image of 55 minutes on a single grey channel.  You can see the vignetting of the smaller filters over the larger CCD chip area.  As you would imagine this nebula would look much better over narrowband filters to expose more of the filamentary structure at the edges of the dark nebula.