Welcome to September, when summer ends and fall begins. This year, Sept. 22 is the date of the “Autumnal Equinox,” the first day of fall.
September is usually a very good month for stargazing. Skies are pretty clear, for the most part. The “Clear Sky Chart” forecast history for Trout Lake shows that 65 percent of nights are clear, exceeded only by July and August. And earlier sunsets allow for viewing before it is very late.
The bright planets will mostly not be in view this month. Dazzling Venus will be low in the western sky after sunset. You’ll need a low view of the western horizon to see it. You can’t miss it; Venus is brighter than any star. Saturn is still visible, also low in the west after sunset.
At the beginning of the month, Saturn will be to the left and slightly above Venus. During the month, Saturn will pass above Venus, and will be to Venus’ right by Sept. 30. An interesting night to find both will be on Sept. 8. The thin crescent Moon will be located just to the left of Venus, and between Venus and Saturn. The bright star Spica will be to the right of Venus. The picture accompanying this article shows how they will look.
September’s Moon will be new on Sept. 5 and full on Sept. 19. On Sept. 9, it’ll be just to the left of Saturn, and above the bright star Antares on Sept. 11.
Fall constellations are beginning to appear in the evening sky, heralding the approach of autumn like the changing color of a tree’s leaves. Pegasus, the winged horse, is now well above the horizon when the sky darkens. You may have trouble picturing the horse (I sure do!), but the constellation has a familiar “square” of equally bright stars that do form an almost perfect square in the sky.
To find the “Great Square” of Pegasus in September, face east, and look about half-way up in the eastern sky. It’ll be a little lower early in the month and a bit higher late in the month. The square will be “tilted” so that one corner is at the top. It is fairly large, as big as the Big Dipper in area. The full Moon will be below the square on Sept. 19.
Look to the north in September, and you’ll find the Big Dipper low in the northern sky. The dipper, and its parent constellation, Ursa Major (the “Great Bear”) are circumpolar, meaning that they never set. If you’re up early in the morning, you’ll find it in the northeastern sky, with the dipper “handle” pointed downward.
Six months from now, the dipper will be high overhead in the evening. During the year, it circles the North Star in our sky, always there to see!