Last modified: Tuesday, December 2, 2003
STAR TRAK/December 2003
Saturn and meteor shower light up December skies
Normally the Geminid meteor shower is the best of the year. Fewer people are willing to brave the cold of a December night to see it, however, so it is less well known than the Perseid shower of August, when only mosquitoes distract a viewer from enjoying the spectacle.
The Geminid shower will peak on the night of Dec. 13-14, when the third-quarter moon will obscure the fainter streaks crossing the sky. If clouds don't spoil the show, observers can expect to see 60-70 meteors per hour at the peak.
The meteors or "shooting stars" will seem to be coming from a point called the radiant near the bright stars Castor and Pollux in the constellation Gemini the Twins, which gives the shower its name. This year the bright yellow planet Saturn will serve as an additional marker for the radiant, which will be well above the eastern horizon a few hours after sundown and will remain high in the sky for the rest of the night. Try facing southeast, though meteors will be visible in all parts of the sky. For details about the Geminid shower, see http://comets.amsmeteors.org/meteors/showers/geminids.html.
More information about meteor showers is available from the American Meteor Society at http://www.amsmeteors.org/showers.html.
The group of sunspots that released several giant bursts of particles toward Earth in October and November, causing auroras that were seen unusually far south in the Northern Hemisphere, has rotated around the Sun and come back into view. It is still spewing masses of material into space, and we may be in for more solar storm activity in December.
Locations of current auroral activity can be seen at http://www.sec.noaa.gov/pmap/. Click on "Aurora Viewing" for tips on when an aurora may be visible in your area. Information about solar and other space "weather" is available at http://www.spacew.com/. Aurora sightings are reported at http://www.spacew.com/www/aurora.html.
To watch for auroras when they are most likely to happen, sign up for solar activity alerts by e-mail at http://skyandtelescope.com/observing/proamcollab/astroalert/default.asp.
Brilliant yellow Saturn will appear low in the eastern sky soon after sunset, dominating the constellation Gemini the Twins. The familiar constellation Orion the Hunter will be on Saturn's right (south) at this time. Saturn is brighter than it has been for almost three decades, and it will reach opposition (be opposite the sun in our sky) on the night of Dec. 31. It will remain about as bright for several weeks, offering those with telescopes their best opportunity to view the planet's famous rings, which are tilted toward Earth almost the maximum amount. Saturn will be visible all night, but the best views will be when it is high in the southern sky around midnight.
Even brighter Jupiter will rise in the east near midnight at the beginning of the month and more than an hour earlier by month's end. Jupiter will be near the constellation Leo the Lion, easily outshining its bright white star Regulus.
Mars has faded from its summer brilliance as it falls farther behind Earth in its slower orbit. The red planet will still be bright and easy to find in the south this month as the evening sky darkens.
Venus will shine brightly low in the southwest at dusk, and it will get higher and even brighter as December moves on, resuming its familiar role as the beautiful "evening star." By month's end it will set two and half hours after the sun.
Mercury will be visible to the lower right (west) of Venus for the first two weeks of the month, but after that it will fade and drop rapidly into the solar glare.
The sun will reach its southernmost point in the sky, called the December solstice, on Dec. 22 at 2:04 a.m. EST (7:04 Universal Time). This will mark the start of winter in the Northern Hemisphere and summer in the Southern Hemisphere. For the next six months, the days will be getting longer in the Northern Hemisphere.
The moon will be full on Dec. 8, at third quarter on Dec. 16, new on Dec. 23 and at first quarter on Dec. 30.