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!

High sunset

Photo of the Week. Sunset from 25,000 feet, the Sun seen through a deep layer of haze.

Astronomy news for the week starting Friday, October 4, 2013.

It's not often that the lunar week (as defined by Skylights) starts so perfectly. But here we are with the Moon in its new phase, passing by the Sun, as we open our new week on Friday, October 4. Given the phase cycle of 29.5 days, just a bit over four weeks, our week is then occupied fully by the waxing crescent. With a clear sky and western horizon, you might first pick it up in twilight the evening of Sunday the 6th. During the early part of our week, as the sky darkens the entire lunar disk is visible, with the nighttime side of the Moon illuminated by sunlight reflected from a bright Earth. As the crescent grows, the effect diminishes, and is lost well before the first quarter, which is passed on Friday the 11th. Watch as the crescent sweeps through the southern part of the Zodiac. The evening of Monday the 7th, the Moon will appear to the right of very obvious Venus. By the following evening, the Moon will be above the planet, with much fainter Antares of Scorpius down and to the left, the three making a nice triangle. On Thursday the 10th, the Moon will pass perigee, where it is closest to the Earth.

Rather difficult to see since it cleared the Sun last March, Venus is now climbing out of western evening twilight, setting around half an hour after the sky is fully dark. It's hard to miss. Then we have a long wait until Jupiter rises, the planet making a grand appearance in the northwest as it comes up in Gemini around midnight Daylight Time southwest of Castor and Pollux. The giant planet then rises high, invisibly crossing the meridian at sunrise. With Mars moving much faster to the east against the stellar background, Jupiter and Mars are now well separated, the red planet rising around 3 AM Daylight. Now seriously in Leo, Mars makes a fine contrast with Regulus, which lies just to the east of it. Meanwhile, back in the west, even though Mercury passes greatest eastern elongation with the Sun on Wednesday the 9th, it is so low as to be overwhelmed by twilight. The little planet invisibly passes five degrees south of Saturn a day later.

Look high in mid evening for Cygnus, the Swan, which, turned upside down, becomes the Northern Cross. At the top is bright Deneb (the Arabic name referring to the Swan's tail), while at the foot we find much fainter Albireo (whose name has no meaning at all). Deneb is the northeast anchor of the Summer Triangle, which also consists of bright Vega to the west and Altair to the south. Between Albireo and Altair flies Sagitta, the Arrow, which looks just like what it is supposed to be. It makes a fine pairing with the little distorted box of stars to the southeast that forms most of Delphinus, the Dolphin. In the northwest, watch the handle of the Big Dipper as it prepares to sink below the pole.
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