Portrait of the constellation of Orion, showing the rich array of bright and dark nebulas within its boundaries. The largest feature is the arc of Barnard's Loop, a possible supernova remnant or stellar wind-blown bubble that encircles Orion. It is officially catalogued as Sharpless 2-276, and is usually plotted as just the easternmost arc, though it extends down and below Orion, all the way over to blue Rigel at bottom right. To the right of Rigel is the purply-blue Witch Head Nebula, IC 2118, a reflection nebula lit by Rigel. Fainter blue nebulosity extends above it. Below the three stars of the Belt of Orion just below centre is the nebulosity in the Sword of Orion that includes the dark Horsehead Nebula and below that the very bright Orion Nebula complex, Messier 42/M43, plus the bluish Running Man Nebula, above it, catalogued as NGC 1973-5-7.
