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September 10: Uranus is stationary
With dark, moonless skies tonight, let’s go galaxy hunting. By 9 P.M. local daylight time, Pegasus is already high in the east, the Great Square easily giving away its location. The northern part of this constellation holds a group of five galaxies, the brightest of which is NGC 7331.
Called the Deer Lick Group, you’ll find this gaggle of galaxies just 4.4° north of 3rd-magnitude Eta (η) Pegasi. NGC 7331 is the easiest to view, a stunning spiral galaxy glowing at magnitude 9.5. If your observing site is particularly dark, you might be able to spot it through binoculars. Any telescope will show it, with larger apertures offering ever more detail. It’s highly inclined to our line of sight, though not exactly edge on, allowing you to see into the center, toward the bright nucleus wrapped in fainter spiral arms. It stretches some 11’ long and 4’ wide.
The four remaining galaxies in this group are sometimes called the “fleas” because they’re much smaller and fainter. They are NGC 7335 (magnitude 13.4), NGC 7340 (magnitude 14.9), NGC 7336 (magnitude 15.0), and NGC 7337 (magnitude 15.2). However, they’re not physically smaller than NGC 7331, but instead much farther away, hinting that this “group” isn’t really a true family, but just a chance superposition on the sky.
Sunrise: 6:37 A.M.
Sunset: 7:15 P.M.
Moonrise: 7:09 A.M.
Moonset: 7:24 P.M.
Moon Phase: Waxing crescent (1%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 10 P.M. local time from the same location.
Alison Klesman is senior editor of Astronomy magazine. She holds a Ph.D. in astronomy and has studied a variety of topics, from minor planets to supermassive black holes.
