M 42 (along with the smaller, circular M 43 above 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.
This image is taken through a filter which allows only the wavelength of
light emitted by this glowing hyrdrogen to pass through, revealing details
of structure that may not be visible in unfiltered views. In this image you
can also see, at the very heart of the Orion Nebula, 4 stars located close
together (look at the "original" size image). This grouping of young,
energetic stars is called the "Trapezium", and the radiation from these stars
lights up the Orion Nebula. The Orion Nebula is 1600 light years from earth,
and about 30 light years across.



Image data:
Camera: Canon 350 XT
Exposure: 30 sec x 58, 5 minutes x 28 (with 7 nm hydrogen-alpha filter)
Telescope: 10" Schmidt-Newtonian, Baader MPCC