M78 is the brightest patch of bluish nebulosity seen in the image above, slightly below the center. It is the brightest diffuse reflection nebula in the sky, located in the rich constellation Orion. M78 is the brightest diffuse reflection nebula of a group of nebulae that include NGC 2071 (northeast, upper left in the image), NGC 2067 (close northwest), and NGC 2064 (close southwest). This group belongs to the Orion Molecular Cloud Complex, which is about 1,600 light years distant from Earth. At its distance, M78 measures almost 4 light years in diameter. As a reflection nebula, M78 is a cloud of interstellar dust which shines in the reflected and scattered light of two 10th magnitude blue (early B-type) stars.

A large number of so-called Herbig-Haro objects, whichb are jets of matter ejected from young stars, can be found embedded in M78, where the stars have just formed. Two of these Herbig-Haro objects, HH19 and HH24, can be easily found southwest (lower right) of M78, they appear in a slightly reddish color.

Sh-2 276 - Barnard's Loop and M78, Wright-Newtonian photograph.