Sky Object of the Month – January 2016
(Courtesy LVAS Observer’s Challenge*)
Messier 78 – Diffuse Reflection Nebula in Orion
(Magnitude 8.3, Dimensions 8’ X 6’)
M78, Orion’s “other” Messier nebula, has the distinction of being brightest diffuse reflection nebula (one whose light comes from nearby or embedded stars) in the sky. M42 and similar bright luminaries like M8, M17, and M20 are basically diffuse emission nebulas that give off their own light.
To find M78, make a low-power scan of the area 3 degrees northeast of Alnitak (the zeta [ζ] star in Orion’s belt – see the finder chart below). M78 was discovered by Pierre Mechain in early 1780 and included by Messier in his Catalog later that year. At an approximate distance of 1600 light years, it spans an area some 10 light years across.