Galaxies in Ursa Major

This is probably my favorite pair of galaxies. They are both fairly bright, and can be seen together through a low-power eyepiece. The contrasting shapes and structures are obvious through a telescope. As a classic spiral galaxy, Messier 81 appears as an oblong glow. Its thin arms, so obvious in this image, are very hard to see through a telescope, but I have glimpsed them with my 18-inch Dobsonian using an eyepiece of moderately high power. Messier 82 has an irregular and chaotic structure, and it has a higher surface brightness. The next two images show closer views of these galaxies. They are about 12 million light years away.

Image details:  A mosaic of two images, each based on a series of 150-second exposures ( 20 for M81, 17 for M82) at ISO 1600, taken with a Canon 400D camera through a Meade 12” telescope at f/5.4.

February 2009