Celestial News: The superb September skies
With cooler evenings and earlier sunsets, September is a superb month for stargazing. Our September skies will feature bright planets and several easy-to-spot star patterns.
On Sept. 6, the first quarter moon will be positioned just about midway between two giant planets: Jupiter to the right, and Saturn to the left. Jupiter is the brighter of the two, outshining Saturn by a factor of 10, but both are easy to see, even before darkness falls.
One night later, on Sept. 7, the moon will have moved eastward in its orbit enough to appear right beside Saturn. The next night, it switches sides on Saturn and then pulls away as its phase waxes toward full.
If you own a telescope, any telescope, aim it at Jupiter and Saturn for two of the biggest “wow” moments that backyard astronomy has to offer. Jupiter will look like a glowing white ball, with two dark stripes across its midsection. The ball of Jupiter might look tiny from nearly half a billion miles away, but remember that you could stuff 1,000 Earth-sized balls inside of Jupiter.
The real thrill of looking at Jupiter, though, is spotting up to four of its giant moons: Io, Europa, Ganymede and Callisto. These four planet-sized moons swing around Jupiter in a matter of days, so they are in different positions every night. On the night of Sept. 15, all four moons will appear on the same side of Jupiter, then, the next night, you’ll see two on one side, two on the other. Jupiter’s moons will look like tiny stars beside their giant master.
Seeing Saturn’s rings through a telescope for the first time is an unforgettable moment. It only takes a telescope of about 50-power to see the icy rings. Look for a little orange companion beside Saturn, too. That would be its only giant moon, Titan.
The moon turns full on the night of Sept. 13. This last full moon of summer traditionally is called the fruit moon. This year’s fruit moon is also a mini-moon, so named because the full moon coincides with the night the moon is farthest from Earth. It’s the opposite of the better-known super moon.
The season of autumn officially arrives for the Northern Hemisphere at 1:50 a.m. Sept. 21. This marks the moment the sun crosses the equator on its way south for the fall and winter. On that day, every location on Earth will experience 12 hours of sunshine and 12 hours of night.
Once the full fruit moon is out of the way, see if you can spot these three star patterns of early autumn. In the northwestern sky, look for the seven bright stars of the Big Dipper, hanging just above the horizon. Follow the curve of the Big Dipper’s handle until you arrive at the bright star Arcturus. In the eastern sky, look for the four bright stars that form the distinctive Great Square of Pegasus, the famed winged horse from Greek mythology.
Finally, look straight up overhead to find the Summer Triangle, formed from three of the season’s brightest stars: Vega, Deneb and Altair.
Jimmy Westlake retired from full-time teaching at Colorado Mountain College’s Steamboat Springs campus in 2017, after 19 years as professor of physical sciences. His “Celestial News” column appears monthly in the Steamboat Pilot & Today. Check out Jimmy’s astrophotography website at http://www.jwestlake.com.
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