Tuesday, November 16, 2010

Watch the Sky Show: the Leonids

Want to wish upon a falling star? This is the week - the Leonid Meteor Shower peaks tomorrow. Earth is currently passing through the “tail” of Comet Tempel-Tuttle. Often called a “dirty snowball,” a comet usually orbits the sun in an elliptical orbit. The comet’s nucleus, consisting mostly of ice and dust, heats as it approaches the sun. Particles begin to stream out behind it and form the comet’s “tail.” As Earth passes through this “tail” the particles collide with the atmosphere and we see a meteor shower.

Best viewing of the Leonids will be just before dawn on Wednesday, November 17 in the eastern sky (see above map). Scientists estimate this year’s show will produce 15 to 20 meteors per hour (a sighting about every 4 or 5 minutes). Meteor showers are notoriously difficult to predict - there may be many more or there may be less.

The waxing gibbous moon will set in Richmond about 4 hours before sunrise tomorrow, so the bright light of the moon will not inhibit viewing in the early morning hours. However, clouds and showers may accompany a cold frontal passage in the Richmond area early Wednesday morning. Let’s hope we get lucky and the skies clear before dawn. But there is another chance - the Leonids may be visible just before dawn on Thursday morning also.

A few tips for best viewing:

 • Find an open area away from city lights with no tall buildings or trees in the eastern sky.
 • Take some friends – it’s always more fun with someone along.
 • Let your eyes relax and look all around - binoculars not required. Actually, your eyes will find the meteors  better without binoculars because they have a broader range of vision.
 • Take some equipment for maximum enjoyment:
        o Lawn chair – be comfortable; kick back and relax.
        o Blankets or sleeping bag – bundle up; it will be chilly (50’s).
        o Hot coffee or tea in a thermos.
 • Binoculars might be useful for observing fireballs, unusually bright meteors that leave an incandescent streak lasting as long as a few minutes. Winds in the upper atmosphere will bend and distort the streak; binoculars will give you a close-up view.

Interesting fact (from http://www.space.com/ ): When a comet takes 33 years to go around the Sun, it goes way out there and tends to get lost. Comet Tempel-Tuttle gets lost a lot. It also gets found now and then. Tempel-Tuttle was "discovered" by William Tempel in late 1865 and independently by Horace Tuttle in early 1866. Nobody saw Tempel-Tuttle again for almost 100 years (1965). Then on March 4, 1997, armed with great orbital data, Karen Meech, Olivier Hainaut and James Bauer at the University of Hawaii "recovered" the comet yet again. Tempel-Tuttle will next return to the inner solar system in 2031.

For more information, go to http://www.space.com/.  Star map credit: Stardate.

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