Spiral galaxy M 81 is located 12 million light years from earth in
the area above the Big Dipper. It is 70,000 light years across, making
it a bit smaller than the Milky Way. M 81 is gravitationally joined to
the smaller galaxy M 82 (see next image in this gallery) in a 100 million
year orbit. The last time these two galaxies passed near each other, it seems
that M 82 was significantly disrupted, while M 81 experienced less disturbance.
However, you can see that some of the spiral lanes in the galaxy have been
pulled out of shape. The gravitational encounter also send waves through the
galaxy's arms, sparking new star formation. The arms of the galaxy are studded
with reddish nebula areas where new stars are forming and lighting up, and
blue splotches which are young star clusters. Below M 81 you can see a smaller
galaxy (designated Holmberg IX)that orbits around M 81.

Image data:
Camera: SBIG STL-11000
Exposure: Luminance 2 hours; RGB 40 minutes each (all 10 minute sub-frames)
Telescope: 12.5" Hyperion