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The Sky This Week, 2011 February 22 - March 1

Count stars for science!
MulCreekFullMoonsmall.jpg
Mulberry Creek by the light of the Full Moon
Taken near Morattico, Virginia, 2011 FEB 20

The Moon wanes in the early morning sky this week.  Last Quarter occurs on the 24th at 6:26 pm Eastern Standard Time.  Luna is now diving toward the southerly reaches of the Ecliptic, passing into the rising constellations of the early summer sky.  Look for her near the bright ruddy star Antares on the morning of the 25th.  In the gathering twilight of the mornings of the 28th and March 1st you’ll see her slimming crescent in the company of the bright glow of Venus.

For the next two weeks you’ll once again have the opportunity to participate in a global survey of the visibility of our night sky.  The 6th annual Globe at Night campaign is underway and will last through March 6th.  This program aims to bring sky awareness to as many people as possible, and with half the world’s population now living in cities it’s especially important to bring the wonders of the night sky to their attention.  The premise is very simple.  All you need to do is go outside between 8:00 and 10:00 pm local time and look for the bright constellation of Orion, the Hunter.  Compare the number of stars that you can see in and around the constellation with the sky charts located on the project’s website, then submit a report.  If you live well away from city light, you should be able to see stars as faint as sixth magnitude.  I was fortunate enough to be visiting such a location last weekend, and I had almost forgotten how densely packed with stars the Orion region is.  My limit was somewhere between 6th and 7th magnitude in the dry breezy sky over Virginia’s Northern Neck.  Back home in the suburbs I’ll be lucky to make out stars much fainter than third magnitude, but all data counts in this study, so don’t be discouraged if you can’t see a sky full of stars.

One “star” that still stands out in the early evening is the planet Jupiter.  Old Jove shines brightly in the fading evening twilight of the western sky, but by the time astronomical twilight ends he’s settling into the extinction of the horizon haze.  You can still catch a decent glimpse of him and his four bright moons with a small telescope, but it’s getting harder each passing night to examine him for detail with higher magnifications.  Enjoy him now, since he only has a few more weeks of visibility left until later in the year.

Saturn now rises at around 9:00 pm in the eastern sky and should be easily spotted a couple of hours later.  He shares the sky with the bright blue-tinted star Spica, some nine degrees to the southeast of the planet.  Saturn sports a warm yellowish hue that belies the frigid nature of his region of the solar system.  His famous rings are made up primarily of water ice as are most of his smaller moons.  The large moon Titan, however, has a dense atmosphere of nitrogen and trace organic molecules, some of which rain down on the surface to produce lakes of liquid methane, ethane, and other exotic compounds.  To be liquid these lakes must be very cold, so don’t let that golden glow fool you!

Venus continues to pursue the Sun along the Ecliptic in the pre-dawn sky.  She gets a visit from the slender crescent Moon as the months turn over.  Even though she remains visible until late in the summer, from now on you’ll get your best views of her in morning twilight.

 

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