Photo of the Week for May 1, 2015
As impressive as face-on spiral galaxies are in photographs, they can be visually challenging. Take M101, also known as the Pinwheel Galaxy, for example. It’s nicely situated above the handle of the Big Dipper and can be detected in binoculars under a dark sky. But add even a modest amount of light pollution, and it all but disappears. That’s because its surface brightness — its luminosity per arc-minute of sky — is relatively low. In other words, most of the galaxy is only a little brighter than the background sky. To see M101 in all its glory, a moonless country night sky is a must. But even a large telescope used under ideal conditions won’t show all the details visible in this image.
Calgary, Alberta, astrophotographer Daniel Meek used an 11-inch Celestron Edge Schmidt-Cassegrain telescope equipped with a QSI 583wsg CCD camera for this 510 -minute LRGB exposure recorded on April 19 and 26, 2015.