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. The third 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 three weeks starting Friday, January 24, 2014.

The next Skylights will appear Friday, February 14. Thanks again for your patience.

Another triple week means another three-fourths of the lunar phase cycle. The Moon begins in the waning crescent phase just past third quarter, which took place Thursday, January 23. Slimming in the eastern sky, the crescent ends at new Moon on Thursday the 30th. At about the same time, the Moon passes perigee, where it is closest to the Earth, which means exceptionally high and low tides at the beaches (not that too many in the north are swimming this time of year). Watch as the crescent goes right under Saturn the morning of Saturday the 25th then well above Antares of Scorpius the following morning. It will appear to the left of the star the morning of Monday the 27th. The Moon then takes on Venus, which is now making a fine morning appearance, rising nearly an hour before dawn by the end of our three-week period. The morning of Tuesday the 28th, the thinning crescent will lie up and to the right of Venus, while the following morning it will be barely visible down and to the left of the planet. Brightening throughout these three weeks, Venus hits maximum brilliance right at the end of the period.

After new Moon, we see the waxing crescent in western evening twilight. The evening of Saturday, February 1, the crescent will pass above the innermost planet, Mercury. While Venus claims the dawn, Mercury does its near best in evening, with its greatest eastern elongation taking place the night of Friday the 31st. The crescent then grows until the Moon hits its first quarter on Thursday, February 6, after which it enters the waxing gibbous phase, which ends at full Moon about the time of Moonrise the night of Friday the 14th, just in time for Valentine's Day. The waxing gibbous will pass a few degrees south of Jupiter the night of Monday, February 10, just a day before it passes its apogee, where it is now farthest from Earth, the difference between perigee and apogee distances about 12 percent. Now high and low "spring" tides are notably diminished.

While Mercury sets in western twilight and Venus just beats out morning's dawn, the other three "ancient" planets sit in the middle. First is Jupiter, which by late evening has already crossed the celestial meridian high to the south, still in Gemini and almost as far north of the celestial equator as it can get. Mars then rises in Virgo an hour or so before midnight, passing five degrees north of Spica on Tuesday, January 28. Saturn then rises in Libra about 2 AM at the start of our period, 12:30 AM at the end.

Sirius, in Canis Major, Orion's larger hunting dog, dominates the evening's stellar sky. If you are far enough south, look for the second brightest star, Canopus (in Carina, the Keel of the ship Argo), which shines 36 degrees south of Sirius. Another 37 degrees farther south lies the South Celestial Pole, which is only visible from south of the Earth's equator. Leaving winter aside, with Leo well up in the east toward midnight, we are getting our first tastes of the stars of spring. Below it and Virgo stream the stars of Hydra, the Water Serpent, the longest constellation of the sky.
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