Dark Horse (astronomy)


The Dark Horse Nebula or Great Dark Horse is a large dark nebula that, from Earth's perspective, obscures part of the upper central bulge of the Milky Way. The Dark Horse lies in the equatorial constellation Ophiuchus, near its borders with the more famous constellations Scorpius and Sagittarius. It is a significant, visible feature of the Milky Way's Great Rift. It is visible from Earth only on clear moonless nights without light pollution and with low humidity.

Name

This region of dark nebulae is called Dark Horse because it resembles the side silhouette of a horse and appears dark as compared with the background glow of stars and star clouds. It is also known as "Great" because it is one of the largest groups of dark nebulae in the sky.

Nearby nebulae

The rear of the Great Dark Horse, is also known as the Pipe Nebula, which itself carries the designation B77, B78, and B59. The Snake Nebula is by comparison a small S-shaped nebula emerging from the west side of the northern part of the bowl of the Pipe.
Barnard 68 is another named dark patch of molecular gas and dust appearing in the Dark Horse Nebula.