Orion in Gas, Dust, and Stars.

The constellation of Orion holds much more than three stars in a row. 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 on the far left 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. Below the frame center and 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. On the upper right lies M42 , the Orion Nebula , an energetic caldron of tumultuous gas , visible to the unaided eye, that is giving birth to a new open cluster of stars. Immediately to the left of M42 is a prominent bluish reflection nebula sometimes called the Running Man that houses many bright blue stars. The above image , a digitally stitched composite taken over several nights, covers an area with objects that are roughly 1,500 light years away and spans about 75 light years.