This exceptional image of the Horsehead nebula was taken at the National Science Foundation’s 0.9-meter telescope on Kitt Peak with the NOAO Mosaic CCD camera. Located in the constellation of Orion, the Hunter, the Horsehead is part of a dense cloud of gas in front of an active star-forming nebula known as IC434. The nebulosity of the Horsehead is believed to be excited by the bright star Sigma Orionis, which is located above the top of the image. Just off the left side of the image is the bright star Zeta Orionis, which is the easternmost of the three stars that form Orion’s belt. Zeta Orionis is a foreground star, and is not related to the nebula.