Skylights featured on Astronomy Picture of the Day

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Skylights featured three times on Earth Science Picture of the Day: 1 , 2 , 3 , 4 .

Mykonos Sunset

Photo of the Week.. The Sun sets slowly over the a Mediterranean island as a cloud drifts to the left. After sunset, a faint sunpillar appears.

Astronomy news for the week starting Friday, January 16, 2004.

Skylights now resumes its regular weekly schedule.

This is the week of the crescent Moon. It starts in its waning crescent phase, when it is seen in the east in the dawn sky, goes through new on Wednesday the 21st, and then starts to wax as a difficult-to-find sliver in the southwest in bright evening twilight the night of Thursday the 22nd. Two days before new, the Moon goes through perigee, where it is closest to the Earth. Be sure to admire the "Earthlight" that lights up the Moon's nighttime side.

Use the Moon to find Mercury. On Saturday the 17th, the little planet, only 39 percent our distance from the Sun, goes through its greatest western elongation, where it is at its maximum angle (a mere 24 degrees) from the Sun and at its best visibility. The morning of Sunday the 18th finds the thin crescent Moon just to the left of the star Antares in Scorpius (which just recently cleared the Sun). Mercury will be well down and to the left of the lunar crescent. The following morning, Monday the 19th, is even better, as Mercury will be directly to the left of the crescent. As always, viewing of Mercury requires a clear, unobstructed horizon.

Venus, on the other hand, requires no guide. Just look in evening twilight in the southwest for the brightest thing you can see. Getting higher each evening, Venus (72 percent our distance from the Sun) does not now set until 8 PM, well after the end of twilight. At the same time, find Saturn nicely up in the northeast in southwestern Gemini, the ringed planet seen high to the south by 11 PM. Then about an hour after Venus sets, Jupiter rises south of the classical figure of Leo. While not rivalling Venus, the giant planet is still amazingly bright. Between Venus and Saturn lies faithful Mars, seen to the west of south at the end of twilight. Entirely in the evening sky now, the red planet sets just before midnight.

As Cassiopeia, the Queen, swings around the northern pole, she is followed closely by Perseus, the Hero of the Andromeda tale. By 8 PM or so, the streams of stars that make Perseus hang high in the northern sky, led by Mirfak, the Alpha star, which gives the name to a bold cluster, the Alpha Persei Cluster. South of Mirfak lies one of the most famous stars of the whole sky, Algol, the Demon Star, an eclipsing binary that "winks" at you, dropping from second to third magnitude and back every 2.87 days. In a dark sky, the Milky Way can be seen streaming out of Cassiopeia through Perseus and then, fading, through southern Auriga, falling thereafter to the east of great Orion.
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