You are here: Home USNO News, Tours & Events Sky This Week The Sky This Week, 2011 March 1 - 8
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The Sky This Week, 2011 March 1 - 8

Still counting stars (there's an app for that), evening planets coming and going.
Orion Rising Thumbnail

Orion rising over Savage Farm
Imaged from near Bluemont, Virginia, autumn 2009

The Moon returns to the evening sky by the week’s end. Between now and then look for her slender waning crescent in the pre-dawn sky, then her waxing crescent after New Moon, which occurs on the 4th at 3:46 pm Eastern Standard Time. Luna shares the pre-dawn sky with bright Venus on the morning of the 2nd. You should have no trouble spotting the 27-hour-old crescent shortly after sunset on the 5th. On the following evening look for Luna just five degrees north of fading Jupiter

Take advantage of any clear nights between now and the 6th to participate in a bit of "citizen science" by counting stars for the "Globe At Night" program. All that’s required to participate is about half an hour of your time and a connection to the Internet. Those of you with smart phones and tablets can also use a webapp to report your findings right from the field. Once again, the idea is very simple. Give yourself about 15-20 minutes to let your eyes become dark-adapted, then go to a location away from the direct glare of artificial lights. Locate the constellation Orion, which will be near the meridian between 7:30 and 8:00 pm, then compare the number of stars that you see with the charts on the Globe At Night website. The goal of the program is to compile 15,000 observations from around the world to measure the distribution of light pollution and dark sky sites. Last year there were over 17,000 contributed observations. If you’re totally skunked by the weather don’t fret; there will be another opportunity to contribute at the end of March during the next "dark of the Moon" period.

Bright Jupiter is now dropping rapidly out of the sky during the early evening. By the end of the week Old Jove sets shortly after the end of evening astronomical twilight, so there’s virtually no time left to catch a final glimpse of him against a dark sky background. In just over a month he will pass behind the Sun, emerging into the morning sky later in the spring. He’ll return to prominence in the autumn sky, reaching opposition in late October.

By the end of the week another planet starts to join Jupiter in the twilight sky. The fleet-footed Mercury eases his way up from superior solar conjunction to begin his best evening apparition for the year. Mercury can be spotted about five degrees above the western horizon on the evening of the 8th at around 7:00 pm, some 10 degrees below Jupiter. One week later the two planets will be just two degrees apart, which should make tracking down elusive Mercury a very simple matter.

Saturn now rises shortly after Jupiter sets in the southeastern sky. The ringed planet’s golden tint stands out in contrast to the icy blue hue of the nearby bright star Spica. By 11:00 pm Saturn is over 30 degrees above the horizon and should present a nice view through steady air in a small telescope. The massive storm that broke out in the planet’s northern hemisphere is still in progress, and owners of medium- to large-aperture telescopes should keep an eye out for this unusual disturbance. Those of us with smaller optics can still enjoy the planet’s wonderful rings, which are now tilted about 11 degrees to our line of sight.

Bright Venus is still prominent in the southeastern sky as morning twilight brightens the horizon. She was a beautiful sight on the morning of the 1st as I began the day looking out over the neighborhood rooftops. Luna will still be nearby on the morning of the 2nd, but you shouldn’t need the Moon to help you find her in the hour before sunrise for the next few weeks.

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