If you wait to celebrate New Year's Eve once in a blue moon, get out the noisemakers. Prepare to rejoice.

New Year's Eve coincides with a Blue Moon, which simply is a second full moon in one month. And although astronomers have yet to agree on where the term originated, this much is known: Blue moons occur once every 2.72 years.

The moon, by the way, won't even look blue, but it will reach -12.7 magnitude, an astronomical measurement of apparent brightness that tells scientists the object is outrageously luminous. You'd be bright, too, if your entire face reflected the sun.

The last Blue Moon occurred in May 1988 and the next one will happen in September 1993, according to the Naval Observatory.

New Year's Eve also marks the official end to the 1980s. Contrary to popular belief, new decades and centuries begin with the year 1.

Don't start reminiscing too soon, though: The last decade is being extended by one second. That allows the cesium-beam atomic clocks at the Naval Observatory to lock step with Earth's rotation (our home planet has slowed down recently).

The Leap Second will be inserted at 23:59:60 Universal Time, or what used to be called Greenwich Mean Time. Here in the United States, the observatory inserts it at 6:59:60 p.m. EST. A Leap Second also was added last year; this one makes the 16th such insertion since 1972.

If you're fortunate enough to live far from city lights, bundle up for a few hours and go outside on Dec. 13 to catch the Geminids meteor shower. Meteors, in general, are nothing more than dust left behind by a comet. On its trek around the sun, Earth passes through many such dust streams. When that happens, the particles strike our atmosphere, glow, burn and (one hopes) provide a spectacular show.

The Geminids show promise: The meteors should start whisking their way through our heavens between now and Dec. 16. The early evening of Dec. 13 will be the peak. The best way to catch meteors is from a dark location. Just look up -- you'll see them.

Meteor showers get their names from the heavenly spot from which they appear to emanate. In this case, it is the constellation Gemini, about halfway up the eastern sky early in the evening. From a meteor-hunting perspective, the apparent origination point won't make any difference.

Astronomers currently credit an asteroid named 3200 Phaethon as the Geminid meteors' parent. That asteroid, astronomers suspect, is a former comet core.

Forgetting the fine, balmy November weather Washington endured won't be hard. Winter arrives at 10:07 p.m. EST on Dec. 21. The sun makes it lowest arc in the sky, supplying the fewest light hours for the northern hemisphere. In fact, the sun is over the Tropic of Capricorn, where it always goes on the Winter Solstice. There is a deeper meaning to the fact of long-gone sun. From the moment of the solstice, we must wait a scant three months before the beginning of Spring. And just a shade more than two months before baseball's spring training.

Hanging brilliantly in the northeast sky, as regal as the mightiest king, the planet Mars outshines any of his neighbors in the Taurus constellation. It will look orange-red in the early evening and, for the rest of the night, floats high across the sky. Now it has reached about -2 magnitude, considered by astronomers to be very bright. By the end of the month, however, it loses its brilliance. Catch the red planet while you can.

Jupiter, that large gaseous planet wooing stars in the late evening, shimmies up from east-northeast at a dazzling -2.4 magnitude. For the moment, allow Mars to have the first billing, since Jupiter will be visible for a while. Find Jupiter huddled between Cancer and Leo after 10 p.m., joining them for a tour of the southern sky. Only cloudy nights could prevent you from finding Jupiter.

Down-to-Earth Events "Blue Planet" -- Film footage from five shuttle missions, scenes from Hurricane Hugo and the 1989 San Francisco earthquake, and other extraordinary views combine in the latest, large-format IMAX film, "Blue Planet." This 42-minute film is a portrait of our ecologically fragile home planet. Shows daily at the Langley Theater, Air & Space Museum. $2.75 for adults, $1.75 for children, students and senior citizens.

Star of Bethlehem -- Find out what the sky looked like 2,000 years ago and discover the possibilities of what the Star of Bethlehem might have been. Arlington Planetarium, adjacent to Washington-Lee High School. Friday and Saturday evenings at 7:30 p.m., Sunday matinees at 1:30 p.m. and 3 p.m. Showing through Dec. 23. Adults, $2; children and senior citizens, $1. Reservations, 703-358-6070.

Dec. 8 -- Take a guided tour of the late autumn sky when the Goddard Astronomy Club presents an opportunity to peer into our night heavens. If you have a telescope, bring it along. Goddard Visitor Center, Greenbelt, 7-9 p.m. Free.

Dec. 12 -- Astronomer Herbert Friedman will discuss the highlights of his new book, "The Astronomer's Universe" (Norton, $24.95). Copies of the book available for purchase and to be autographed, 7:30 p.m., Arlington Planetarium. Adults, $2; students and senior citizens, $1. Reservations, 703-358-6070.

Dec. 23 -- Gil Onlon, mission manager for the Solar, Anomalous and Magnospheric Particle Explorer (SAMPEX), explains the studies of solar energy particles and galactic cosmic rays. 1 p.m. Goddard Visitor Center. Free.