The stars of autumn begin to push those of summer out of the way as the nights grow longer and cooler. Pegasus is in view in the east as night falls, with several related constellations following the flying horse into the sky over the next few hours.
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In the Sky This Month
September 23: Double Double
Epsilon Lyrae stands quite close above Vega, one of the brightest stars in summer and autumn skies, which is high overhead at nightfall. Epsilon Lyrae consists of two pairs of stars. Each pair is tightly bound, with the two pairs quite far apart.
September 24: Puffiest Planet
HAT-P-67b, a giant planet in Hercules, is about as dense as cotton candy. Hercules is high in the west at nightfall, to the right of the Keystone — four moderately bright stars that outline the strongman’s body. The system is too faint to see without a telescope.
September 25: Scutum
Scutum, a small, faint “shield” of stars, scoots across the southwestern sky on these early autumn nights. It represents the coat of arms on the shield of John Sobieski, a 17th-century king of Poland and one of that country’s great national heroes.
September 26: Moon and Saturn
Saturn, the second-largest planet in the solar system, is in great view tonight. It stands just a few degrees from the gibbous Moon, which is the width of a couple of fingers held at arm’s length. It looks like a bright star.
September 27: Old Clusters
A pair of globular star clusters is in the southeast at nightfall. M15 is highest in the sky, to the upper right of the Great Square of Pegasus and high above the almost-full Moon. M30 is lower, in Capricornus. Through binoculars, each looks like a fuzzy star.
September 28: Harvest Moon
Tonight is the night of the Harvest Moon, which is the full Moon closest to the autumnal equinox. In ages past, its extra light helped farmers harvest their autumn crops before the onset of cold weather.
September 29: Heading West
Lyra, the harp, is high overhead at nightfall. Its leading light, Vega, is one of the brighter stars in the night sky. In the 1800s, the government built observatories in the western U.S. to use Vega and other bright stars to establish the exact locations of cities and towns.
Last September 6, 5:21 pm
New September 14, 8:40 pm
First September 22, 2:32 pm
Full September 29, 4:58 am
Times are U.S. Central Time.
Apogee September 12
Perigee September 27
The full Moon of September is the Fruit Moon or Green Corn Moon. This year it’s also the Harvest Moon.