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The Sky This Week, 2010 October 12 - 19

An Ancient Story of the Season

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Jupiter, 2010 OCT 11, 01:45 UT
Imaged with the USNO's 30.5-cm (12-inch) f/15 Clark/Saegmüller refractor


The Moon skims along the southern horizon this week, passing through the setting summer constellations before climbing back towards the north through the fainter stars of autumn. First Quarter occurs on the 14th at 5:27 pm Eastern Daylight Time. Luna lies just above the teapot-shaped asterism formed by the brighter stars of Sagittarius, the Archer, on the evening of the 13th. From there she treads a lonely path until the night of the 19th, when she passes about six degrees north of bright Jupiter.

The middle of October is one of my favorite times of the year. The seasonal change is almost as dramatic as the one that takes place in the spring, but instead of awakening from a long winter’s slumber the Earth is preparing for the coming lean times. Right now it feels as if my neighborhood is under some sort of siege as the oak trees drop their seemingly endless supply of acorns, while farther north the colors of changing leaves splash a riot of color over the landscape. These changes can be found steeped in the sky lore of cultures around the world. One of my favorite sky stories comes from the Native Americans of my New England home and involves one of the most recognized star patterns in the sky. Every year during autumn the seven stars that form the "Big Dipper" asterism graze the northern horizon during the late night and early morning hours of mid-October. The Big Dipper is part of the larger constellation of Ursa Major, the Greater Bear, in our Greco-Roman sky myths. To the natives who lived in the Berkshire Mountains of western Massachusetts and Connecticut, the Dipper also represented a bear, or at least the stars of the Dipper’s "bowl" did. The three stars of the handle represented three hunters, who chased the bear around the sky all year until this time of the year, when they finally caught it and killed it. The flaming red color of the changing maple trees in their world were thought to be stained by the blood shed from the bear’s wounds. If you look closely at the star that forms the "bend" in the Dipper’s handle, you might see a faint star nestled next to the brighter one. This was the pot that the hunters would use to cook the slain bear!

The early evening still offers keen-eyed skywatchers a fleeting glimpse of the planet Mars. He is currently traversing the faint stars of Libra on his way toward a conjunction with his ruddy rival, the star Antares, in November. You’ll probably need binoculars to pick the red planet out in the deepening twilight of the west-southwest sky, where he sets an hour and 20 minutes after sunset.

Much easier to spot is giant Jupiter, whose bright glow may be seen low in the east shortly after sunset. As the sky darkens he climbs higher into the southeastern sky, and by the end of evening twilight he is well placed for telescopic viewing. He now culminates high in the south at around 11:30 pm, which allows for several hours of fascinating viewing through the telescope. Jupiter’s four large "Galilean" moons offer an endlessly shifting configuration from night to night, while his famous Great Red Spot offers an interesting and colorful target for patient observers who observe him at the right times. Good nights to look for the Spot this week are the evenings of the 15th and 17th at around 10:00 pm EDT.

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