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Photo of the Week. Peaceful winter sunset.

Astronomy news for the two-week period starting Friday, January 2, 2009.

Welcome to the New Year. May 2009 be good to you.

Starting the week as a fat waxing crescent just shy of first quarter, which is passed on Sunday, January 4, the Moon spends the rest of the first week of our fortnight growing in the waxing gibbous phase. Full Moon is then reached on Sunday the 10th, after which our companion will enter the waning gibbous as it heads toward third quarter the night of Saturday the 17th. Perigee, where the Moon is closest to Earth, falls on the same day as the full Moon, resulting in especially high tides at the coasts.

Though the Moon will pass north of Uranus on Friday the 2nd, the only real encounter of note is with Leo and Saturn. Take a look the night of Monday the 12th, around 11 PM, when the Moon will lie just to the west of Regulus. By the next evening, the Moon will have flipped to the other side of the star, falling between it and Saturn, while the night of Wednesday the 14th, the Moon will be seen a few degrees to the south of the ringed planet, the Moon, Saturn, and Denebola (at Leo's tail) all in a row toward the north.

During our two-week interval, both the inner planets reach their greatest eastern elongations relative to the Sun. Mercury gets there first, on Sunday the 4th, when it will be seen near Jupiter (the giant planet becoming lost to twilight). Venus then repeats the act on Wednesday the 14th. Look the night of Friday the 9th to see Jupiter, Mercury, and Venus all in a row upward from the horizon. Shining gloriously in the southwest, Venus does not now set until around 9 PM. Though the Sun will henceforth begin to catch up with it, since the Sun is now setting later, so will Venus until early in February.

The Earth made the show last December when it passed the Winter Solstice, and now does it again by passing perihelion on Sunday the 4th (a popular date), where it will be closest to the Sun, 91,400,000 miles (147,096,000 kilometers) away, 1.107 percent closer than average. Given the northern weather, solar distance obviously has little to do with the seasons, which are caused by the tilt of the Earth's axis. Our proximity to the Sun will enhance the tides still further.

Early January is home to one of the finer meteor showers of the year, the Quadrantids, which emanate from the defunct constellation Quadrans (the Quadrant), which once marked stars to the east of the Big Dipper's handle. Capable of producing close to two meteors a minute, the shower will be best viewed the morning of Saturday the 3rd, and the farther west the observing site the better.

Switching from the northern sky to the southern, Sirius, the bright Dog Star, crosses to the south around midnight, bringing along with it the vastness of Argo, the Ship of the Argonauts. For northerners, the most accessible of the three parts into which the Ship is now divided, Puppis (the Stern), wraps itself to the east and south of Sirius's constellation, Canis Major.
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