M 42 (along with the smaller, circular M 43 below it) is the brightest
diffuse nebula in the northern sky. It can be seen with the unaided eye as a
fuzzy "star" in the middle of Orion's sword. The nebula is a place of
new star formation, and radiation from the cluster of young, bright
stars at its center causes this part of a huge hydrogen gas cloud to glow.
The Hubble Space Telescope has revealed more than 150 stars in the
nebula which are surrounded by protoplanetary disks, the early stages
of new solar systems. The Orion Nebula is 1600 light years from
earth, and about 30 light years across.

Image data:
Camera: Canon 350XT
Exposure: ISO 800, 5 minutes x 13; 20 seconds x 20
Telescope: 10" Schmidt-Newtonian