in Orion, 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 1800s.
The red 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.
Streams of gas leaving the nebula are funneled by a strong magnetic field.
Bright spots in the Horsehead Nebula's base are young
stars just in the process of forming.
Light takes about 1500 years to reach us from the Horsehead Nebula.
The above image was taken with the 0.9-meter telescope at Kitt Peak National Observatory.