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Historic 'conjunction' happening in December - PostBulletin.com
A "conjunction" is when two or more astronomical bodies appear to be close together from our view on Earth.
This December starts with a full moon. While the first full moon is officially on Nov. 30, for all practical purposes, the night sky will be saturated with virtually full moonlight the first several days of December, pretty much killing serious stargazing. After about Dec. 4, evening skies get much darker.The biggest celestial headline this December is the historic conjunction between Jupiter and Saturn. A "conjunction" is when two or more astronomical bodies appear to be close together from our view on Earth. This conjunction between Jupiter and Saturn is monumental. The last time these two planets were this close together was when Galileo was still living! Since this past summer, the two great planets have been pulling closer and closer to each other. This month, they can be easily seen in the low southwestern sky toward the end of evening twilight, setting about one hour later. At the start of December, Jupiter and Saturn will be less than 2 degrees apart. Thats about the width of two of your fingers held together at arms length. Jupiter is the brighter of the two, to the lower left of Saturn. On Dec. 21, which coincidently is the winter solstice, Jupiter and Saturn will only be a 10th of a degree apart! This is the closest these planets have been to each other in the sky since 1623, when Galileo was still alive. Another marquee event this December is the annual Geminid meteor shower, one of the best of the year. This will be an excellent year for the Geminids, because there will be no moonlight in the sky overnight. The Geminid meteor shower peaks on the night of Dec. 13-14. Ill have much more on the Geminids next week. Even without all of the special happenings this December, this is a great month for stargazing. Mars continues to fade after its big show in October, but its still the brightest star-like object in the southern evening sky. You might still be able to spot some of its surface features with a moderately sized telescope. The great horse Pegasus is riding high in the south-southwestern sky not too far away from Mars. In the high northern heavens is Cassiopeia the Queen, resembling a big, bright W. The Big Dipper is still very low in the north, but youll notice that it begins evenings higher and higher in the northeast sky, standing diagonally on its handle. The Little Dipper is hanging by its handle above the Big Dipper, with Polaris, the North Star, poised at the end of the handle. Gazing to the east, just after evening twilight ends, youll be bombarded with all kinds of bright stars, and even more as you get later in the evening. You are witnessing the rise of the winter constellations, the best ones of the year, in my opinion. Auriga the Chariot Driver and Taurus the Bull lead the charge. Just above Taurus is the best star cluster in the sky, known both as the Pleiades and the Seven Little Sisters. This is a young group of stars, 410 light-years away, that looks like a tiny Big Dipper. After 8 p.m., Orion the Hunter, the grand centerpiece of the winter constellations, climbs well above the eastern horizon. The three equally spaced stars in a row that make up the belt of the great hunter will definitely jump out at you. Enjoy all thats going on in nightly celestial theater this month. Its more than worth bundling up for! Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, Stars, a Month by Month Tour of the Constellations published by Adventure Publications. Send questions to [email protected] The Rochester Astronomy Club welcomes new members and puts on public star parties. Their website is rochesterskies.org.