Object Information:                  The Horsehead Nebula (B33), IC 434
                                                Morphological Type - Dark Nebula (B33), Emission Nebula (IC 434)
                                                Constellation - Orion,
                                                Location -  R.A. 05:40.9, Dec. -03:09,
                                                Distance - 1,500 light years,

Description:    The Horsehead Nebula is one of the most recognizable of deep sky objects by virtue of its distinct resemblance to its namesake.  It is certainly the best known example of a dark nebula. The Horsehead is also known by the less descriptive Barnard 33.  The nebula is a classic dark nebula and may only be seen because it is silhouetted against the very faint glow of IC 434, a reef of tenuous emission nebulosity.

Burnhams Celetial Handbook reports that the Horsehead was first detected in photographs in 1889 by E. Pickering.  Burnhams  also reports that the significance of this object was not immediately recognized.  Early descriptions refer to this object as a "bay" or a gap in IC 434.  It appears that E. Barnard was the first to recognize that it was actually obscuring light from behind.

The Horsehead is believed to a dense cloud of tiny interstellar grains of dust that blocks the light of the emission nebula IC 434 and stars behind.  While dark nebula are generally invisible (except of course where back lit as in the case of the Horsehead), their dust grains very effectively absorb light and ultraviolet radiation and then re-radiate this energy at infrared wavelengths.

The Horsehead nebula is one of the most difficult of visual objects and requires dark skies and large aperture to view.  Also seen in the lower left corner is NGC 2024, commonly known as the "Flame Nebula"; the open cluster NGC 1981 and the reflection nebulosity complex of NGC 1973, 1975 and 1977 ["The Running Man Nebula"] can be seen to the far right.

Imaged at:                                 San Diego Astronomy Association site near Tierra del Sol, San Diego County, California;
                                                 Elevation - 4000 feet

Equipment:                                Optics - Takahashi E-160 Newtonian at f/3.3
                                                 Mount - Losmandy G-11,
                                                 Camera -Nikon FM2,                                                
                                                 Filter - none,

Exposure Information:               November 24, 2001
                                                 A median combination of four, 40 minute exposures; Guided using the SBIG STV,

Image Acquisition Software:     N/A,

Image Processing Software:      Registration and combination of images - RegiStar, Final processing - Photoshop 6.01

Image Processing Steps:            1)  All images were registered and stacked [average combination] using Registar,  2)  Final processing and conversion to JPEG format was performed using Photoshop 6.01.

    The CCD image of the Horsehead below was taken with a Takahashi MT-160 Newtonian in November 2001.  It is a median combination of four 15 minute exposures.