Galaxies M81 & M82 in Ursa Major
In the theme of interacting galaxies, I share with you two galaxies in the Big Dipper, called M81 (the spiral one on the right) and M82 (the
cigar shaped one on the left).  These two galaxies, about 12 million light years away, passed close to one another about 20 million years
before the light began its journey to my camera.  Obviously, the galaxies are now further apart than this image shows, but we won't see that
for another 12 million years....confused yet?

During this close encounter event, the larger and more massive M81 dramatically deformed M82 by gravitational interaction.  The galaxies are
still close together, their centers separated by a linear distance of only about 150,000 light years.

M81 was originally discovered by Johann Elert Bode, who found it, together with its neighbor M82, on December 31, 1774. A few years
later, Messier added them as the 81st and 82nd objects in his catalog of comet-lookalike fuzzies through a telescope.  

The image above added 40 minutes of Ha-filtered exposures to accent areas of hydrogen emission nebulosity (red regions), combined with 60
minutes luminance, and 30 minutes each of red, green, and blue exposures.  An ST10XME camera was used through a TEC 140 mm
refractor and an AP 0.67x reducer.
Music by Enya