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!

Jupiter in Taurus

Photo of the Week.. Jupiter in Taurus in November of 2012. The Hyades and Aldebaran are to the right, Pleiades above, southern Auriga to the left.
See Jupiter in Taurus in 1988-89 and in 2001-02, when the planet also met up with Saturn.

Astronomy news for the two weeks starting Friday, December 7, 2012.

The holiday season necessitates a series of two-weekers. The next Skylights will appear December 21, 2012. Thanks for your continuing interest and patience.

This particular fortnight is also the result of the fine Geminid meteor shower, which peaks the night of Thursday, December 13 and the morning of Friday the 14th. Seen for a day or so before and after the peak, the shower spans Skylights' usual transition time, giving us a chance to highlight it. Easily as good as August's Perseids, in a dark sky you can expect a couple meteors a minute that seem to emanate from the constellation Gemini. The Geminids are the leavings of the "asteroid" 3200 Phaethon, which is now believed to be a dead comet. So dress warmly and enjoy the holiday show, which will be best in the morning hours.

And unless you are surrounded by artificial lighting, the sky will indeed be dark, as new Moon takes place at the same time, on Thursday the 13th. Having passed third quarter on Thursday the 6th, the Moon spends the first week of our period in morning's waning crescent, then during most of the second week in evening's waxing crescent, at least until it hits first quarter on Wednesday the 19th, after which we see a bit of the waxing gibbous. As the crescent wanes, it will make a fine passage below the star Spica the morning of Sunday the 9th, be seen a bit farther below Saturn the following morning, then end with a delightful passage just below Venus the morning of Tuesday the 11th. Look for Mercury down and to the left of them.

Rising just after 5 AM or so, Venus will be a steady guide to Mercury, which is now sliding down the morning sky toward the Sun (as is Venus, which is becoming notably lower and dimmer). Going in the opposite direction, Saturn rises around 3:30 AM in the middle of our period and is well up in the southeast by the time twilight begins to light the sky. The evening, for that matter most of the night, is lit well by Jupiter. Hard to miss, the brightest starlike object in the sky until Venus rises, the giant planet continues to hang out in Taurus more or less north of the Hyades and Aldebaran. In minimal planetary news, Uranus ends its retrograde motion and begins moving easterly against the stars of Pisces just as the Geminid shower comes to fruition.

We bookend the fortnight with the Sun, which passes two important points in its apparent celestial motion. At 5:12 AM CST (6:12 EST, 4:12 MST, 3:12 PST) the morning of Friday, December 21st, the Sun passes its southerly extreme at the Winter Solstice in Sagittarius, beginning astronomical winter and giving North America the shortest day and longest night. By the time it rises, as far to the southeast as possible, the Sun will have begun moving northward toward the Vernal Equinox and spring. However, because of the Earth's orbital eccentricity coupled to the tilt of its rotational axis against the orbital perpendicular, earliest sunset takes place as we start our period, so that by the time of solstice passage the evenings will already have begun to lighten.

Rising in early evening, at midnight, mighty Orion stands tall with Gemini up and to the left, Taurus up and to the right, and Auriga above both of these. To the left of him lies Canis Minor, and farther down, Canis Major with Sirius, the brightest star of the sky.
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