Spiral Galaxy, Ursa Major
Mag 6.9, size 21’x10′
200mm f8 RC at f6 (Revelation x0.75 reducer)
Piggyback guiding with 70mm f/7 refractor
L 10×240s 2×2, RGB 10×120s 4×4 Darks Bias Flats
Atik 460EX (-25C), LRGB filters, IDAS P2 LPR filter
Captured in APT, Processed in Nebulosity3, PS CC, LightRoom
Terrible trouble with LP, noise and flats. Hard to process out the flaws.
Messier 81 (also known as NGC 3031 or Bode’s Galaxy) is a spiral galaxy about 12 million light-years away in the constellation Ursa Major. Due to its proximity to Earth, large size and active galactic nucleus (which harbors a 70 million M☉ supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy’s large size and relatively high brightness also make it a popular target for amateur astronomers.
Messier 81 was first discovered by Johann Elert Bode on December 31, 1774. Consequently, the galaxy is sometimes referred to as “Bode’s Galaxy”. In 1779, Pierre Méchain and Charles Messier reidentified Bode’s object, which was subsequently listed in the Messier Catalogue.