Skylights featured on Astronomy Picture of the Day

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Skylights featured nine times on Earth Science Picture of the Day: 1 2 3 4 5 6 7 8 9 -- Full List Restored!

Greenland 10

Photo of the Week. Planet Earth: the fifth of twelve in the "Flight across Greenland," going from east to west above the fantastic glacier and a river of ice. See full resolution.

Astronomy news for the week starting Friday, February 28, 2014.

Having passed new the night of Friday, February 28, the Moon spends the entire week in its waxing crescent phase, which finally ends at first quarter on Saturday, March 8, shortly before its daytime rising. Your first look at the thin early crescent will be in western twilight the evening of Sunday the 2nd. The evening of Thursday the 6th finds the fattening crescent below the Pleiades in Taurus and to the right of Aldebaran and the Hyades. There are no planetary visitations except for one with Uranus, the Moon passing two degrees north of the distant planet on Monday the 3rd.

This is an extraordinary week for "stationary" planets. Since the planets all orbit counterclockwise around the Sun as seen looking down from the north, their general movements as seen from Earth are toward the east against the background of the stars. But Earth is moving too. As we pass by a more slowly moving outer planet, or a faster inner planet passes by us, the planet appears first to stop in its tracks ("stationary" against the stars), reverse its motion (becoming " retrograde," moving to the west), then after opposition to the Sun (or inferior conjunction for an inner planet) becoming stationary again as it resumes its easterly trek. Copernicus had this all worked out in the 16th century. This week, five (count 'em, 5) bodies of the Solar System become stationary. In all Skylight's years, there's not been such a remarkable coincidence.

Transiting the meridian high to the south shortly after the end of evening twilight, setting around 3:30 AM, Jupiter becomes stationary on Thursday the 6th as it ends retrograde within the confines of Gemini southwest of Castor and Pollux and begins to head toward Taurus. All the other five are starting retrograde. Rising around 9:30 PM in Virgo northeast of Spica, Mars stops and begins westerly retro on Saturday the 1st. Rising half an hour before midnight in Libra, Saturn starts retro just over a day later. They respectively transit the meridian about 3 and 4:30 AM, oppositions with the Sun not taking place until early April and May. The remaining two involve asteroids, both in eastern Virgo. Ceres, with a diameter of 560 miles (910 km)the largest of them, becomes stationary on Saturday the 1st, a mere hour before Mars does it, while Vesta, the brightest (almost visible to the naked eye and easy to see in binoculars) does it on Wednesday the 5th, the oppositions of both coming in mid-April.

That leaves us with Venus and Mercury, the latter brilliant and obvious in southeastern morning skies, Mercury not rising until a bit after dawn and hard to see. A telescope will show Venus as a crescent, the planet revealing only a portion of its sunlit hemisphere. Adding to the odd "stationary" coincidence, Mercury did it last Thursday, February 27.

While the winter constellations of evening shift off to the west, with southern Argo sailing after them, look to the northeast to see the Big Dipper of Ursa Major climbing the sky and to the northwest for the descending "W" of Cassiopeia. Due north, at an angle above the horizon closely equal to your latitude, find perpetual Polaris, which lies less than a degree from the North Celestial Pole, about which the sky seems to turn.
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