Sky Watch

Early Birds Can Glimpse Mars, Mercury and Jupiter

By Blaine P. Friedlander.
Special to The Washington Post
Monday, December 4, 2006; Page B04

Like a holiday cornucopia, December's heavenly horn is filled with plenty.

Early risers this month can spy the planetary trio of Mars, Mercury and Jupiter conspiring in the eastern sky just above the horizon. Look for them Sunday morning, when the brightest will be Jupiter (at negative first magnitude, bright) sitting just below Mercury (zero magnitude, less bright). Mars will be to the right of the other two planets at first magnitude (relatively dim compared to the other two planets).

Over the rest of the month, Mercury moves out of view, and Mars and Jupiter rapidly split apart -- but both remain in the same eastern region of the sky until the rising sun washes them out. Jupiter will remain bright.

At the beginning of December, Venus is relatively obscure. But after a few days, if you look to the west-southwestern sky at dusk, the effervescent planet slowly emerges from the sun's glare. Day by day, it gets higher in the west after sundown.

Venus (negative third magnitude, very bright) is about eight degrees above the western horizon in mid-month and will ring in 2007 from about 12 degrees above the horizon after the last sunset of the year.

Venus is an early-evening object, but look out for the ringed Saturn much later in the night. Right now, it ascends the east-northeastern heavens about 11 p.m. By mid-December, Saturn (zero magnitude, bright) starts rising about 10 p.m. Throughout the month, it will hang high in the post-midnight heavens all night.

Winter officially starts at 7:22 p.m. Dec. 21, according to the U.S. Naval Observatory. This is the solstice, when the sun appears to touch the Tropic of Capricorn. In reality, the sun is not moving; Earth is moving on its annual orbit around the sun.

Over several weeks after the solstice, there will be more daylight -- and it will keep getting lighter until late June.

Roughly two weeks before the winter solstice, Washington will have its earliest sunsets. Since Saturday and until Dec. 11, sunsets are at 4:46 p.m., according to the U.S. Naval Observatory.

The city's latest sunrises will occur Dec. 31 to Jan. 10, when the sun will rise at 7:27 a.m.

On clear and cold mid-December nights, look up to find the Geminid meteors. They peak in the pre-dawn hours of Dec. 14, according to the American Meteor Society. Meteors are dirt specks left behind in comet trails, and as Earth passes through the dirt stream, the specks strike the atmosphere, creating brilliant streaks.

With the Geminid meteors, the parent "comet" is actually thought to be asteroid 3200 Phaethon, now considered an extinct comet traveling along the same path as the Geminids.

Down-to-Earth Events

Dec. 5 -- Just in time for the holidays, astronomer Elizabeth Warner will discuss "Buying a Telescope? Things to Consider" at the University of Maryland Observatory open house, College Park. 8 p.m. Sky-watching will follow, weather permitting. http://www.astro.umd.edu/openhouse/index.html

Dec. 9 -- Astrophysicist Ted Gull of NASA's Goddard Space Flight Center will explain the extraordinarily bright star Eta Carinae at the National Capital Astronomers meeting at the University of Maryland observatory, College Park. 7:30 p.m. http://www.capitalastronomers.org

Dec. 20 -- Learn how to use a computer to observe the heavens. Phil Wherry of the Northern Virginia Astronomy Club explains eyepiece selection, object visibility and making a good viewing sequence for observing. The talk will be at the University of Maryland Observatory open house, College Park. 8 p.m. See the cosmos after the lecture, weather permitting. http://www.astro.umd.edu/openhouse/index.html

Dec. 21 -- About 20 minutes after "The Day of the Sun's Return: The Winter Solstice" begins, winter will commence as the sun begins creeping back toward the northern hemisphere. The program will be at the Montgomery College planetarium in Takoma Park. 7 p.m. http://www.montgomerycollege.edu/Departments/planet

Blaine Friedlander can be reached at PostSkyWatch@aol.com.

© 2006 The Washington Post Company