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The Sky This Week, 2013 March 5 - 12

Don't forget to change your clocks! (and why...)

Jupiter on the wane, with its moon Io
Imaged 2013 March 5, 01:50 UT

The Moon wanes in the pre-dawn sky this week. New Moon occurs on the 11th at 3:51 pm Eastern Daylight Time. She begins the week in the company of the stars of Sagittarius, the Archer, one of the signature constellations of summer. On the morning of the 8th she brushes just a degree south of the third magnitude star Dabih in the constellation of Capricornus, the Sea-Goat. From then through the end of the week she wends her way through the barren stars of early autumn’s sky.

Yes, you read it correctly in the last paragraph. This is the weekend when we advance our clocks to Daylight Time. This is supposed to happen at 2:00 am local time on the morning of Sunday the 10th, but most everyone sets their clocks before retiring on Saturday night. The rules governing Daylight Time have varied quite a bit since the concept was first introduced in the U.S. at the end of World War I. In concept the idea promoted extended time for arms production under natural light, conceivably saving energy. First codified in 1918, the rule was quickly rescinded in 1919. For the next few decades Daylight Time observance was left up to individual states. Federal rules did not come into play until 1966. Since then the beginning and ending of Daylight Time has been set by the Uniform Standard Time Act and its amendments. The most recent of these was passed in 2005 and became effective in 2007. We will stay on Daylight Time until November 3rd this year. Interestingly we now spend about a month longer on Daylight Time than on "Standard" time, which makes me wonder what "Standard" time should really be. The USNO has no say in the matter, though. Enforcement of the Time Act and its various laws are the responsibility of the Department of Transportation!

This week is the third campaign for the international Globe At Night "citizen science" program. This world-wide effort to document the brightness of the sky and increase sky awareness was born in the International Year of Astronomy in 2009. The idea is simple: collect data from people around the world by counting the stars visible from any location. This month you have the choice of two constellations, Orion and Leo. Orion is on the meridian as evening twilight falls, while Leo is best seen after 10:00 pm EDT, high in the eastern sky. Whichever constellation you use, all you need to do is to compare your view of the sky with the star charts on the project’s website and answer some simple questions on your observing environment. It’s a great family activity and demonstrates that even simple things can contribute important information to science.

Despite the threat of a late season snowstorm here in Washington, I was quite pleased to see an old friend returning to the sky as I packed up my telescope for the night. The bright, rose-tinted star Arcturus was peeking over the roofline to the east. This star, the brightest in the northern sky, is a sure sign of approaching spring. Look for its solitary glow in the east during the late evening.

Jupiter seems to get a reprieve in the evening hours thanks to the switch to Daylight Time. In reality he’s still well west of the meridian as twilight fades, but now you don’t have to drag the telescope out until after dinnertime to get a good look at him. The giant planet is still the brightest star-like object in the sky, and even though his apparent disc has shrunk to 80% of his opposition size he still offers a wealth of details for the modest instrument.

Saturn’s entry into the sky gets pushed back an hour thanks to the clock change, so after Daylight Time takes over you’ll once again have to stay up until 11:00 pm to see him come up. By the same token you won’t have to get up quite so early to catch him in the morning sky. It will still be dark at 6:00 am EDT and Saturn will be just west of the meridian. A quick view of this far-flung world with his mysterious rings is just the way to start off another day!

USNO Master Clock Time
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