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!

Morning clouds

Photo of the Week. Morning thunder.

Astronomy news for the two weeks starting Friday, December 16, 2011.

Skylights will next appear December 30, 2011.

And a happy holiday season to all. Our fortnight pretty much spans the lunar crescents, starting with the last quarter on Saturday, December 17. It then runs through the eastern morning waning crescent to new on Christmas Eve around noon in North America, then switches to the western skies as the evening waxing crescent, which will grow until first quarter on New Year's Eve. The night of Wednesday the 21st, the Moon will pass perigee, where it is closest to the Earth.

The night of Friday the 16th sees the Moon several degrees to the southwest of Mars. Then the morning of Monday the 19th, the Moon will rendezvous with Saturn and its current partner Spica, to the west of the ringed planet, while the following morning it will below the pair. As the Moon then thins, on the morning of Thursday the 22nd, it will appear to the right and a bit up from Mercury, which will be making a nice appearance in dawn's light. After the new phase, next look for the Moon to the right of very obvious Venus the evening of Monday the 26th, then above it the following evening. In far lesser events, the crescent will pass north of Neptune on Wednesday the 28th, while (to complete the year) similarly taking on Uranus on Saturday the 31st.

Planets are all over the sky. Venus hath arrived, for sure. Look into the southwest in late twilight to see it glowing brightly above the horizon, not setting until half an hour or more after the sky gets fully dark. Next up is Jupiter, which crosses the meridian by 8 PM and does not set until shortly after 2 AM. Still south of classical Aries, Jupiter ceases retrograde motion on Monday the 26th, thereafter resuming its normal easterly trek against the stars. More than an hour before midnight, Mars then rises to the south of Leo's hindquarters, the red planet crossing the meridian just before morning twilight begins. That leaves Saturn and Mercury. The ringed planet, beautifully positioned in Virgo to the northeast of Spica, rises just a hair before Jupiter sets. Our smallest planet actually rises in the morning dark just before dawn, and on Thursday the 22nd, passes seven degrees north of Antares, goes through greatest western elongation relative to the Sun, and, as noted above, appears a bit down and to the left of the waning crescent Moon. In a lesser event, Pluto goes through conjunction with the Sun on Thursday the 29th.

Our own Earth makes bigger news, as the Sun passes the Winter Solstice in Sagittarius at 11:30 PM CST on Wednesday the 21st (10:30 MST, 9:30 PST, 12:30 AM EST on the 22nd) to mark the beginning of astronomical winter. On that date, with the Sun as far south as it gets (overhead at the Tropic of Capricorn), we in the northern hemisphere will have our shortest day and longest night of the year.

Though winter is upon us, the northern sky still presents a set of autumn constellations. In early evening, look for the "W" of Cassiopeia a bit to the west of overhead. Farther west is the dim pentagon-shaped figure of her husband, Kingly Cepheus, while to the east lie the star-streams of the hero Perseus, the rescuer of Andromeda, who lies south of the Queen.
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