M81_m82

Messier 81 (left) and Messier 82 (right) are a pair of interacting galaxies in the constellation Ursa Major. They are relatively close - astronomically speaking! - to our own Milky Way Galaxy, since their distance is estimated to be about 12 million light years. The two galaxies are separated by about 150,000 light years. German astronomer Johann Bode discovered them in 1774, thus M81 is also referred as Bode''s galaxy and sometimes both galaxies are called Bode''s Nebulae, although M82 is more often referred as the Cigar galaxy.

M81 can be seen with binoculars and small telescopes and a few observers have reported seeing it with just their naked eye under exceptional seeing conditions. With large telescopes M81 presents an exceptional sight, the \"grand design\" spiral arms becoming visible extending outwards from the core. Its mass has been calculated to be around 250 billion suns, while the galactic nucleus harbors a supermassive black hole with a mass of about 70 million suns.

Astronomers studying the motions of the two galaxies believe that a few hundred million years ago, a close encounter took place between the two galaxies. As a result, tidal forces have deformed the shape of M82 and triggered massive star formation, so M82 is classified as a prototype starburst galaxy. Photographs of M82 taken with large telescopes reveal a bipolar outflow of material emanating from the core of the galaxy, where the rate of star formation has increased ten-fold compared to \"normal\" galaxies.

M81 and M82 are part of the Messier 81 galaxy group, one of the nearest galaxy groups to our Local Group. Up to now 34 galaxies have been identified as members of this group, including M81, M82 and NGC 3077, the small galaxy seen at upper left. Our Local Group of galaxies (with the Milky Way and Andromeda as the largest members) and the M81 group are in turn members of a larger group, called the Virgo Supercluster of galaxies.

Thanks to all for looking - clear skies!

Image Details:

Telescope: Orion EON ED 80/500 refractor

Mount: Modified Vixen Sphinx (NexSXW)

Camera: Canon EOS 20Da

Light frames: 11 x 2 mins (total: 22 mins), ISO 1600, Daylight WB

Guiding: Skywatcher 80/400 refractor, Skywatcher Synguider autoguider

Date & Location: 2/5/2019 - Chalkidiki, Greece

Processing: DSS 4.1.1, Adobe Photoshop CS6 with Astronomy Tools Actions Set (spikes added to brightest stars)