Orion: Belt, Flame, and Horsehead.

What surrounds the famous belt stars of Orion? A deep exposure shows everything from dark nebula to star clusters, all embedded in an extended patch of gaseous wisps in the greater Orion Molecular Cloud Complex . T h e brightest three stars, appearing diagonally on the left of the featured image are indeed the famous three stars that make up the belt of Orion . Just below Alnitak , the lowest of the three belt stars , is the Flame Nebula , glowing with excited hydrogen gas and immersed in filaments of dark brown dust. Just to the right of Alnitak lies the Horsehead Nebula , a dark indentation of dense dust that has perhaps the most recognized nebular shapes on the sky. The dark molecular cloud , roughly 1,500 light years distant, is cataloged as Barnard 33 and is seen primarily because it is backlit by the nearby massive star Sigma Orionis . The Horsehead Nebula will slowly shift its apparent shape over the next few million years and will eventually be destroyed by the high-energy starlight.