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The Sky This Week, 2012 January 31 - February 7

Bright Moon, bright planets, and Groundhog Day!
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Jupiter, 2012 FEB 1, 00:07 UT


The Moon brightens the evening sky this week, passing high above the bright stars of the Great Winter Circle. Full Moon occurs on the 7th at 4:54 pm Eastern Standard Time. February’s Full Moon is popularly known as the Snow Moon or Hunger Moon, indicative of the hardships often associated with the season’s harshest month. This year, though, at least in the Washington area, we’ve had virtually no snow and some of my spring bulbs are starting to bloom! Look for Luna between the Pleiades star cluster and the bright star Aldebaran on the evening of the 1st. On the night of the 5th she may be found halfway between the bright star Procyon and the Twin Stars of Gemini, Castor and Pollux.

February 2nd is one of the most celebrated "non-holidays" on the calendar. Groundhog Day is definitely a big deal for the folks who live in western Pennsylvania near the town of Punxsutawney, and it was also a big enough deal to inspire a movie set in that rustic locale. Most people in the U.S. and Canada take at least some passing interest in the dawn activities at Gobbler’s Knob and the prognosticative powers of a large indigenous rodent whose "mystical" powers were translated from a tradition brought over to America by German immigrants. Loosely based on the old pagan celebration of Imbolc, it was believed that if a hibernating animal awoke and saw its shadow there would be six more weeks of winter. No shadow indicated an early spring. Imbolc and its derivatives mark one of the so-called "cross-quarter" days in the ancient seasonal calendar, marking the mid-point of astronomical winter. Halloween is another one of these cross-quarter days that are still widely observed here in the New World, continuing traditions that date back millennia in time.

This is a banner week to explore the varied terrain of our nearest neighbor in space with the telescope. The Moon offers a variety of interesting formations unlike any that you will find on the Earth. The stark lighting of the Sun on the Moon’s airless landscape casts deep black shadows along the terminator line, exaggerating the geographic relief of mountain ranges and crater depths. The phases between First Quarter and Full are my favorite times to go Moonwatching from my front yard, and despite having looked at the same features for many years I always find some detail I’d never noticed before. Just about any telescope will give you a satisfying view, so find a lunar map online and start exploring her for yourself!

You’ve probably been noticing that the bright planets Venus and Jupiter are edging closer to each other in the early evening sky. Venus is continuing to move rapidly eastward from the advancing Sun while Jupiter is gradually losing ground to the day-star. Both planets offer fine targets for the small telescope during these early evening hours. Venus presents a dazzling gibbous phase that will slowly wane as the disc grows larger over the next few months. Jupiter sports his four bright moons as well as his ever-changing cloud belts, but you’ll need to set up early in the evening to see him at his best. As he settles toward the western horizon the Earth’s atmosphere degrades the view of the more delicate details in Jupiter’s turbulent cloud tops. The two planets will continue to close ranks during February, and by mid-March Venus will pass Old Jove by.

Towards the end of the week you’ll notice a bright ruddy object rising shortly after the Moon in the eastern sky. This is Mars, which is rapidly climbing into the evening sky as he prepares for his opposition in early March. Mars and the Moon are the only two objects in the solar system where you can glimpse features on a solid surface, and while Mars’ apparent diameter this opposition is a paltry 14 arcseconds, you can still easily see his bright north polar ice cap and some of his darker surface features with a modest telescope.

Saturn follows Mars over the eastern horizon by about three hours. The ringed planet is still best viewed before dawn and is worth the effort to view if you get the chance. Saturn’s rings are now quite open to our line of sight, and they will continue to be as the planet approaches opposition in mid-April.

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