Messier 78 (also known as NGC 2068) is a reflection nebula that spans some 4 light years, about 1,600 light-years away in the constellation Orion, just to the north of Orion’s Belt.
M78 is the brightest diffuse reflection nebula within the Orion B molecular cloud (LDN 1630) that also include NGC 2071, NGC 2067, NGC 2064 and NGC 2024 (the Flame Nebula).. Two bright supergiant stars, HD 38563A and HD 38563B are responsible for making the cloud of dust in M78 visible by reflecting their light.
About 45 variable stars, young stars still in the process of formation as well as some 17 Herbig-Haro objects are known in M78. These Herbig-Haro objects are presumably jets of matter ejected from young stars embedded in the nebulous matter of M78 where they have just formed.
Infrared investigations have given a clearer image of the open cluster of young stars which have formed in this nebula. From investigations astronomers concluded that much of the young, embedded star formation is occurring in clusters, including the formation of lower mass stars. They counted a number of 192 stars, spread over an area of 7′ angular diameter.