If you were disappointed
with the meager showing put on by this year's Leonid meteor shower, don't fret.
What could be the best meteor display of the year is scheduled to reach its
peak on Monday night, Dec. 13.
Skywatchers with dark skies
away from city lights could see one or two meteors every minute during the Geminid
meteor shower. The greatest activity is expected to be visible from North America,
Europe and Africa.
The Geminids get their name
from the constellation of Gemini, the Twins. On the night of this shower's maximum,
the meteors will appear to emanate from a spot in the sky near the bright star
Castor in Gemini. [Sky
Map ]
Typically strong
The Geminid meteors are
usually the most satisfying of all the annual showers, even surpassing the famous
Perseids of August. Studies of past displays show that this shower has a reputation
for being rich both in slow, bright, graceful meteors and fireballs as well
as faint meteors, with relatively fewer objects of medium brightness.
Geminids typically encounter
Earth at 22 miles per second (35 kilometers per second), roughly half the speed
of a Leonid meteor. Many Geminids are yellowish in hue. Some even appear to
form jagged or divided paths.
The Earth moves quickly
through this meteor stream. Rates increase steadily for two or three days before
maximum. So over the weekend, viewers between midnight and dawn might see a
shooting star every few minutes. The number of meteors drops off sharply after
the peak. Renegade forerunners and late stragglers might be seen for a week
or more before and after maximum.
Ideal conditions
The Geminids perform excellently
in any year, but British meteor astronomer Alastair McBeath has expects a "superb
year" in 2004. Last year's display was seriously compromised by bright
moonlight, when a bright gibbous Moon came up over the horizon during the late
evening hours and washed-out many of the fainter Geminid streaks.
But this year, the Moon
will be at New phase Dec. 11. On the peak night, the Moon will be a skinny crescent,
low in the west-southwest at dusk and setting before 6 p.m. That means the sky
will be dark and moonless for the balance of the night, making for perfect viewing
conditions.
According to McBeath, the
Geminids are predicted to reach peak activity on Monday at 22:20 GMT, which
is 5:20 p.m. EST. Locations from Europe and North Africa east to central Russian
and Chinese longitudes are in the best position to catch the very crest of the
shower, when the rates conceivably could exceed 120 per hour, or two every minute.
[Predictions
for Select Cities]
Maximum rates persist at
only marginally reduced levels for some 6 to 10 hours, McBeath says, so other
places, such as North America, should enjoy some fine Geminid activity as well.
When to watch
Indeed, under normal conditions
on the night of maximum activity, with ideal dark-sky conditions, at least 60
to 120 Geminid meteors can be expected to burst across the sky every hour on
the average. Light pollution greatly cuts the numbers, so city and suburban
dwellers will see far fewer.
Generally speaking, depending
on your location, Gemini begins to come up above the east-northeast horizon
right around the time evening twilight is coming to an end. So you might catch
sight of a few early Geminids as soon as the sky gets dark. There is a fair
chance of perhaps catching sight of some "Earth-grazing" meteors.
Earthgrazers are long, bright
shooting stars that streak overhead from a point near to even just below the
horizon. Such meteors are so distinctive because they follow long paths nearly
parallel to our atmosphere.

Jimmy Westlake
imaged this Geminid in 1985. Click to enlarge it. More about the image below. |
The Geminids begin to appear
noticeably more numerous in the hours after 10 p.m. local time Monday, because
the shower's radiant is already fairly high in the eastern sky by then. The
best views, however, come around 2 a.m. Tuesday, when their radiant point will
be passing very nearly overhead. The higher a shower's radiant, the more meteors
it produces all over the sky.
How to prepare
This time of year, meteor
watching can be a long, cold business. The late Henry Neely, who for many years
served as a lecturer at New York's Hayden Planetarium, once had this to say
about watching for the Geminids: "Take the advice of a man whose teeth
have chattered on many a winter's night - wrap up much more warmly than you
think is necessary."
Hot cocoa or coffee can
take the edge off the chill, as well as provide a slight stimulus. It's even
better if you can observe with friends. That way, you can keep each other awake,
as well as cover more sky.
Give your eyes 15 minutes
or more to adapt to the darkness before getting serious about meteor watching.
And have something comfortable to sit on; a lounge chair will allow you to stare
up for long periods without straining your neck.
Geminids stand apart from
the other meteor showers in that they seem to have been spawned not by a comet,
but by 3200 Phaeton, an Earth-crossing asteroid. Then again, the Geminids may
be comet debris after all, for some astronomers consider Phaeton to really be
the dead nucleus of a burned-out comet that somehow got trapped into an unusually
tight orbit.
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Geminid
Forecast for Select Cities
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Meteor
showers are notoriously difficult to predict, but the Geminids are
relatively reliable. In addition to the Monday night peak, Sunday
night could provide a good show. This chart shows expected rates
of meteors every 15 minutes for select locations. However, these
rates won't actually be visible from cities, due to urban lighting.
CLICK
TO ENLARGE
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Joe Rao
serves as an instructor and guest lecturer at New York's Hayden Planetarium.
He writes about astronomy for The New York Times and other publications, and
he is also an on-camera meteorologist for News
12 Westchester, New York.
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From
Jimmy Westlake:
"Back in 1985,
I was teaching and directing the Rollins Planetarium at Young Harris
College at the base of Georgia's highest mountain peak, Brasstown Bald
(Yes, Georgia has mountains!).
"The 4784-foot
mountain often served as my private observation spot at night, as it
did on the night of December 13-14, 1985 during the Geminid meteor shower.
I aimed my tripod-mounted Nikon FE-2 camera toward the celestial pole
and stopped down the lens to f5.6 for a 60-minute exposure. Several
meteors flashed by during the hour, but none were bright enough to record
at f5.6.Two
airplanes, headed for parts unknown, left their silent trails across
the film. The silhouette of the tower housing the Information Visitors
Center and observation deck is visible atop the peak, 200 feet above
me.
"After the
hour-long exposure, I placed my gloved hand over the 50 mm lens, carefully
opened the aperture ring to f1.8, and waited for 5 minutes. I then removed
my hand from in front of the lens for a final 30 second exposure to
punctuate each star trail with a bright dot. As fate would have it,
during that 30-second interval, the brightest Geminid fireball of the
night shot right across the center of the image! My main concern was
not bumping the tripod as I jumped up and down in excitement!
"The result,
as you can see, is a striking portrait of a Geminid meteor."
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