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Starwatch NewsletterMinnesota Starwatch is a newsletter describing the night sky in the Midwest.
It is updated monthly, and is produced by the |
Minnesota Starwatch for January 2007
It takes a hardy star-gazer to brave the icy nights of January, but the month's clear, cold skies can offer some rewarding sights for those who have the foresight to dress warmly and direct their gaze to the heavens above.
This month, Venus will rule the skies, while many of the other planets are biding their time for more prominent appearances in later months. Venus, the queen of the evening sky, will appear low in the southwest about 30 minutes after dusk as the month begins. Gradually Venus will mount higher in the sky and remain longer. By the end of January, Venus will be visible for nearly two hours.
Saturn will also be well worth watching this month as it lights up the late evening sky in the east. Look for Saturn in the vicinity of Regulus, the brightest star in the constellation of Leo the Lion. On January 6th, you'll be able to see the moon appear between Saturn and Regulus near sunset.
The moon also plays a part in a pretty picture that will greet the early riser on the morning of January 15th. Jupiter, the crescent moon and the ruddy star Antares will line up in the southeastern sky about 45 minutes before sunrise.
As always, the moon will offer some lovely images this month. Of all the heavenly bodies, the moon holds perhaps the most interest for non-astronomers. From "once in a blue moon" to "the moon was a ghostly galleon tossed upon cloudy seas," poets and other literary folk have not been reluctant to adopt the moon for their own purposes. One old Scottish folk ballad has a frightened man warning his master of a bad omen. "Last night," he says, "I saw the new moon with the old moon in her arms."
As anybody who has read the Ballad of Sir Patrick Spens knows, somebody should have listened to the man's warning. When the moon starts acting up, things are not going to end well. But what exactly did the man see?
Modern astronomers have a more plain-spoken name for the phenomenon. They call it "earthshine." The term refers to reflected sunlight which appears to "fill out" the crescent moon with a faint illuminated outline of the entire disc.
Of course, the moon doesn't generate any light itself. We say that the moon waxes and wanes, but naturally it's the pattern of sunlight reflected off the surface of the moon that appears to expand and contract as the moon travels in its orbit around the earth. The sliver of a crescent represents the portion of the moon's illuminated surface visible from Earth. Direct sunlight accounts for the bright crescent, but, because of reflected light from the earth's surface, the darkened remainder of the disc can also been seen at times, thanks to "earthshine."
You can see the "new moon with old moon in her arms" just at dusk on January 20th. We can't swear that there won't be any bad omens involved that evening, but we do promise that the viewer will have the pleasure of seeing a nice conjunction of the crescent moon with the lovely evening star, Venus. It's probably well worth the risk.
For fun Astronomy Outreach programs check out our Public Outreach link, or if you're interested in how you can help build the new Minnesota Planetarium, please call 612-630-6151 or visit http://www.mplanetarium.org.
The Minnesota Starwatch is produced by the University of Minnesota Astronomy Department.