Photo of the Week for August 14, 2015
Just off the western side of the distinctive W shape of the constellation Cassiopeia, lies a pair of deep-sky treasures — one easy to see, the other difficult. The easy one is the pretty open cluster M52, which can be viewed in binoculars. The difficult object is the Bubble Nebula, catalogued as NGC7635. Although it shows up well in photographs like this one by Eric Remy of Quebec City, Quebec, the Bubble is best seen in a moderate- or large-aperture telescope equipped with a special high-contrast observing filter.
Remy’s portrait of the pair digitally combines 41, 180-second exposures (for a total exposure exceeding two hours) captured with a Canon EOS Rebel T3i DSLR camera mated to a Sky-Watcher 100ED f/9 refractor telescope equipped with a Astro-Tech AT2FF field flattener.