Galaxy M81, at a distance of 12 million light-years (4-fold further than the Pinwheel Galaxy and Andromeda Galaxy), is one of the brightest galaxies in our skies. From a
dark sky site, a few astronomers with exceptional vision can spot its faint glow with the naked eye. The spiral shape can be revealed with small telescopes. The prior
image on my website shows its companion galaxy M82 which was disrupted by a close encounter with M81 tens of millions of years ago.
M81 was originally discovered by Johann Elert Bode on December 31, 1774, who found it, together with its neighbor M82. To this day, M81 carries the name "Bode's
Nebula." Charles Messier added them to his catalog in 1781.
The image above was taken from a dark sky site using 80 minutes luminance, 100 minutes red, and 50 minutes each of green and blue exposures, all unbinned. I used an
ST200XM camera through a TEC 140 mm refractor. The image below was obtained in a light polluted suburb with Luminance exposure of 145 minutes and R-G-B
exposures of 30-30-50 minutes, for a total exposure time of 4 hours 15 minutes. I used an ST10XME camera through a TEC 140mm refractor telescope.
Music: Thick as a Brick, by Jethro Tull
This music was selected because M81 has the mass of our galaxy, but
only 1/3 its size, making its density comparitively "thicker".