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University of Minnesota
September 21, 2011
This artist's rendering depicts planet Kepler 16b and the two stars it orbits.
Image credit: NASA/JPL/Caltech/R. Hurt. Wikimedia Commons
By Deane Morrison
Take advantage of the clear, crisp nights to watch October's celestial show. Headliners this year are Mars and the moon.
About two hours before dawn on the 1st, grab your binoculars and look to the east. You'll see the bright star Regulus, in Leo, and above and slightly to its right the reddish beacon of Mars. On that morning, the Red Planet appears in the midst of the lovely Beehive star cluster of Cancer—a stunning sight.
Mars is a planet on the move, however. Throughout the month it pushes on toward Regulus, and in November the planet and star will have a close encounter.
Jupiter is high and even more brilliant than usual, overpowering everything else in the sky with it. The planet is at opposition on the 28th, when Earth glides between the planet and the sun. At that time Jupiter will appear opposite the sun in the sky, rising around sunset and setting near sunrise. No need to worry about finding it; if you go out later than an hour or so after sunset and face toward the south, it will be obvious.
The full hunter's moon will be a beauty, rising the evening of the 11th, only three hours before true fullness. This moon gets its name from the proximity of hunting season, which follows the fall harvest and the fattening of deer.
The Great Square of Pegasus reaches its highest point in the south during the prime evening viewing hours. Look just below it for the dimmer but pleasing Circlet of Pisces, representing one of the fishes in the constellation. The bright star far to the south is Fomalhaut, the mouth of Piscis Austrinus, the southern fish.
The Summer Triangle of bright stars still lingers high in the west after sunset. Recently, while searching the sky for extrasolar planets, NASA's Kepler space telescope discovered a Saturn-sized planet orbiting not one but two stars about 200 light-years from us. The stars circle each other at a distance of about 20 million miles while the planet, Kepler 16b, orbits them from a distance of 65 million miles from the center of the system.
Living on such a planet, you would see two stars—one big and orange, the other small and red—rise and set every day and sometimes even barrel right past each other. And, of course, you would cast a double shadow. No wonder Kepler 16b immediately picked up an unofficial moniker: Tatooine, after "Star Wars" character Luke Skywalker's home planet, which also orbited two suns.
October closes with Halloween, an ancient Celtic holiday marking the start of the dark half of the year. On that night, evil spirits that had been cooped up for six months (since May Day) were set free upon the world. Woe to farmers who had not harvested their crops by then, for the spirits were sure to spoil them. Offerings of food and bright lights to ward off the spooks turned into our tradition of trick-or-treating and lighted jack o' lanterns. Halloween, known to the Celts as Samhain (rhymes with CHOW-when), was one of four cross-quarter days falling midway between an equinox and a solstice.
The University of Minnesota offers public viewings of the night sky at its Duluth and Twin Cities campuses. For more information and viewing schedules, see:
Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/planet
Twin Cities, Minnesota Institute for Astrophysics (during fall and spring semesters): www.astro.umn.edu/outreach/pubnight
9/22/11 Contact: Deane Morrison, University Relations, (612) 624-2346, firstname.lastname@example.org
Find U of M astronomers and links to the world of astronomy at http://www.astro.umn.edu.