Stunning blue nebula
Reflection nebula Messier 78 is 1,350 light-years from Earth. The blue colour comes from reflected starlight.
Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow — its dust particles simply reflect the starlight that falls on them.
Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1,350 light-years away in the direction of the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion’s belt.
Image credit: ESO and Igor Chekalin.