From my Sunday night astro imaging run: the Pinwheel Galaxy...
From my Sunday night astro imaging run: the Pinwheel Galaxy (M101, NGC 5457) is 21 million lightyears away in the constellation Ursa Major. It’s quite a bit bigger than our own galaxy: a 170,000 lightyear diameter and a trillion stars. We’re looking 21 million years back in time on this beautiful galaxy, tilted perfectly, face-on (or top-down?) from our perspective in the Milky Way, so that we can clearly see its spiral form, twisting dust lanes, HII regions, and other detailed structures. Space is big. And it takes that long for the light of a trillion suns to reach us from this distant galaxy. Imaging notes: about 6 hours of data, 70 x 300-second exposures with the ZWO ASI071 color camera cooled to -10C, UV/IR Cut filter, 800mm f/4 newtonian scope. With a 28.8 arc-minute apparent size, M101 is about the limit for deep sky targets with the 800mm focal length scope.
