The Horsehead Nebula can be found in the constellation of Orion. Its distinctive dark silhouette is a cloud of cold dust and gas that blocks light from the brighter emission nebula behind it.
Also catalogued as Barnard 33, the Horsehead lies within the much larger Orion molecular cloud complex, a stellar nursery about 1,375 light-years from Earth. The nebula is visible in long-exposure photographs near Alnitak, the easternmost star in Orion’s Belt.
The shape resembles a horse’s head only because of the arrangement of the obscuring dust against the glowing background. It is not a separate galaxy or a bright, self-luminous object like a star. The reddish glow surrounding it comes from ionized hydrogen in the broader nebular region.
A common mix-up is with the Orion Nebula, another famous object in the same constellation. The Orion Nebula is a bright stellar nursery, while the Horsehead is primarily recognized as a dark nebula silhouetted against illuminated gas.