In 2013, we have a bright waxing gibbous moon lighting
up the peak nights of the annual Geminid meteor shower. The peak is tonight
(night of December 12-13) and tomorrow night (December 13-14). Which night is
better? Either is good, but the moon will set earlier tonight than tomorrow
night, leaving a few dark hours for meteor-watching just before dawn breaks.
Take advantage of that dark pre-dawn sky window! In the Northern Hemisphere,
this meteor shower often rates as one of the best – if not the best – shower of
the year on a dark, moonless night. You can often see up to 50 or more meteors
per hour in a moonless sky.
Although the Geminids favor
the Northern Hemisphere, this shower is also visible from the tropical and
subtropical parts of the Southern Hemisphere. At temperate latitudes in the
Southern Hemisphere, the meteor numbers tend to be lower.
Can you watch the shower in
moonlight? You can try. The Geminids are known for sporting respectably bright
meteors, so you might see a decent sprinkling of Geminids on these upcoming
moonlit nights. As a general rule, the Geminid meteor shower starts around
mid-evening (at mid-northern latitudes) and tends to pick up steam as evening
deepens into late night. No matter where you live worldwide, the greatest
number of meteors usually fall in the wee hours after midnight, or for the few
hours centered around 2 a.m. local time. If you’re game, you can watch the
Geminid shower all the way from mid-evening until dawn.
If you’re watching in
moonlight, you’ll see the most meteors when the moon is lowest in the sky.
Shortly before the moon sets, try sitting in a moon shadow with an otherwise
open view of the sky to optimize your chances of catching some meteors.
Or just go to bed early and get up before dawn. At northerly
latitudes, the showerradiant point –
near the bright star Castor in the constellation Gemini – stays out until dawn. This custom sunrise calendar will help you learn the time of moonset at
your precise location, on these nights. Be sure to click the option for
moonrise/moonset times.
The Geminids are a consistent
and prolific shower. Although The shower typically produces 50 or more meteors
per hour – or an average of about one every minute – keep in mind those are the
numbers you can expect on a dark, moonless night.
Meteors often come in spurts and are interspersed by lulls, so give yourself at
least an hour of observing time. Simply sprawl out on a reclining lawn chair,
look upward and enjoy the show.
Although Friday night until
Saturday morning will probably present the peak night of the Geminid meteor
shower, tonight might be almost as good – especially since there will be less
moonlight to obtrude on the show.
Where do the meteors come
from? Although meteors are sometimes called ‘shooting stars,’ they have nothing
to do with stars. Instead, they are strictly a solar system phenomenon. Around
this time every year, our planet Earth crosses the orbital path of a mysterious
object called 3200 Phaethon, which might be an asteroid or a burnt-out comet
orbiting our sun. Debris from this object burns up in the Earth’s upper
atmosphere to give us the annual Geminid meteor shower. The moderately fast
Geminids slice through the Earth’s atmosphere at some 35 kilometers – or 22
miles – per second.
The Geminid meteors are named
for the constellation Gemini the Twins, because the radiant point of this shower lies in front Gemini, closely
aligning with the bright star Castor. If you trace all the Geminid meteors
backward, they all appear to originated from this constellation.
But you don’t need to know the
constellation Gemini to see the meteor shower. The Geminid meteors will streak
across all parts of the heavens from late night until dawn.
Bottom line: Find a dark sky
to watch a seasonal attraction, the Geminid shower, on the nights of December
12-13 and 13-14, 2013. The moon will interfere, but, especially on the December
12-13, you will have a window of darkness between moonset and dawn. Plus the
Geminids tend to be bright. You might catch a few in the moonlight. If you
watch, the Geminids are sure to add to your enjoyment of holiday lighting these
next few nights!
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