An Etymological Dictionary of Astronomy and Astrophysics

A large → H II region in the north part of → Orion’s Sword composed of reflection and emission components ( → reflection nebula, → emission nebula). It includes NGC 1977, NGC 1975, and NGC 1973, separated from each other by a → dark nebula which resembles a running man, as well as the → open cluster NGC 1981. NGC 1977, the designation some sources use to describe the entire complex, is the largest and brightest nebulous component first described by Herschel in 1786. The nebula is approximately 40 arcmin in apparent diameter, and 1,500 → light-years distant.

See also: Nebula number 279 in the second edition of the → Sharpless catalog.