The Horsehead Nebula (aka Barnard 33 in the bright nebula IC 434) is a dark nebula in the Orion constellation.
The nebula is located just south of Alnitak, the star furthest east on Orion's Belt. It is approximately 1500 light years from Earth.
The darkness of the Horsehead is caused mostly by obscuring dust, although the lower part of the Horsehead's neck casts a shadow to the left.
Streams of gas leaving the nebula are funneled by a strong magnetic field. The nebula is also an active star forming region.
To the lower left of the Horsehead is the blue reflection nebula NGC 2023.