Photo of the Week for June 17, 2016
German astronomer and mathematician Johann Elert Bode swept up this beautiful spiral galaxy in 1774 — seven years before Charles Messier added it to his list of non-comets as M81. Of course neither Messier nor Bode understood the true nature of this “nebulous patch,” as Bode described it. M81 is one of the nearest galaxies beyond our Local Group. Glowing at magnitude 6.9, it’s also one of the brightest galaxies in the sky. As with many deep-sky objects, M81 reveals its most intricate details only in long-exposure photographs like this one by Saint-Liboire, Québec, imager Martin Bernier.
Martin captured this galactic portrait last February with a QSI 683wsg-8 cooled CCD camera attached to an Astro-Tech AT12IN 12-inch f/4 imaging Newtonian reflector telescope. The final image combines seven hours total exposure shot through four different filters.