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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!

Esquel pallasite

Photo of the Week.The Esquel (Argentina) pallasite is a stony iron meteorite with large mineral crystals. It probably came from the mantle-core boundary of a smashed up asteroid. A piece of the Sikhote-Alin iron is at the far right. (From the Goose Kaler memorial meteorite collection at Staerkel Planetarium).

Astronomy news for the week starting Friday, April 11, 2014.

A busy week lies ahead (or lay behind, depending on when you read this). The Moon starts off in the waxing gibbousphase as it grows to full the night of Monday, April 14 (really the morning of Tuesday the 15th), when it will undergo a fine total eclipse that's visible throughout almost all of North America plus western South America (but not in Europe). It then rather anticlimactically spends the remainder of the week in the waning gibbous phase, which is terminated at third quarter next week, on Monday the 21st. The evening of Sunday the 13th finds the Moon to the west of Mars. By the following night, it will have flipped to the other side. The morning of the eclipse the darkened Moon will be in a lovely setting just to the northeast of Spica, with Mars to the west. The morning of Wednesday the 16th, the waning Moon goes just south of Saturn.

The heart of the eclipse begins at 12:58 AM CDT the morning of Tuesday, April 15, when the full umbral shadow of the Earth takes its first bite out of the leading (eastern) edge of the lunar disk. The partial phase ends when the Moon enters totality at 2:07 AM, which maximizes at 2:46 AM with the northern edge of the Moon just missing the central core of the shadow. The Moon starts to leave full shadow, when it gets the first glimpse of sunlight, at 3:25 AM, and then completely leaves the full shadow behind at 4:33 AM, not long before moonset. Add an hour for Eastern Daylight Time, subtract one for MDT, two for PDT, three for Alaska, and five for Hawaii. Even in totality, though quite dark and red, the Moon is visible as a result of sunlight scattered and refracted by the Earth's atmosphere into the umbral shadow. The degree of darkness depends on the state of the Earth's atmospheric blanket, particularly on recent volcanic action that makes it more opaque. Since the Moon passes just south of the central shadow, the northern limb of the Moon will be the darkest at mid-eclipse. The penumbral stages, where the Moon is in just partial earth shadow, are not much worth bothering with, though the effect can be seen as a slight dimming just before and after the main eclipse.

In addition to the eclipse, we get to admire a fine array of planets. First up is Jupiter, which has already entered the high western sky by the time the sky is dark, and is with us until 2 AM. By midnight, reddish Mars, making a fine color contrast with Spica to the southeast, has also crossed the southern divide. Just past opposition to theSun, the planet's motion is obvious over only a few nights. It makes its closest approach to the Earth (0.62 Astronomical Units, 93 kilometers, 58 million miles) for this orbital round on Monday the 14th. Next is Saturn, which rises just past the end of evening twilight and crosses to the south around 3 AM. Finally, just before dawn, Venus rises in the east and takes over the sky, not fading away in the until bright morning twilight.

If that is not enough, Venus passes less than a degree north of Neptune on Saturday the 12th, Vesta (the brightest asteroid) and Ceres (at 470 km, 290 miles, the largest) both go through opposition to the Sun (respectively on Sunday the 13th and Tuesday the 15th), and Pluto begins retrograde motion on Monday the 14th.

From Mars and Spica, look toward the north to the brightest star in the northern hemisphere, Arcturus, the Bear Driver, who follows Ursa Major around the northern pole. As Ursa Major's Big Dipper passes nearly overhead, the Little Dipper of Ursa Minor rises up to meet it.
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