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The Webfooted Astronomer - November 2001

 

Leonids-the Event of the Year?

THE Leonid meteor shower is a sight of a lifetime when they storm, and they are predicted to storm in large numbers this year. The Leonid meteors are debris from Comet 55P/Tempel-Tuttle, which was discovered on December 19, 1865, by Ernst Wilhelm Liebrecht Tempel in Marseilles, France, and by Horace Parnell Tuttle of Harvard College Observatory, Cambridge, Massachusetts, on January 6, 1866.

Could this be the year we see a storm? There are several models predicting the Leonid meteor shower. In spite of the predictions, surprises can always occur. Remember the fireballs of 1998 on the night before the predicted peak? In light of this, itís best to monitor the nights around November 17, 18 and 19 - before, during, and after the maximum.

According to the Armagh Observatory (http://www.arm.ac.uk/leonid/encounters.html), the times of maximum Leonid activity and the estimated meteor rates are as follows:
Nov. 18, 10.01 UT, 2500/hr, visible from N. & Central America
Nov. 18, 17.31 UT, 9000/hr, visible from Australia & E. Asia
Nov. 18, 18.19 UT, 15000/hr, visible from W. Australia, E., SE & Central Asia

The moon will be close to new for the shower. So get out to a dark site to increase your meteor rates. Your latitude will also affect how high the Leonid radiant will get in your sky, which affects rates.

The Leonids will have a general radiant at 153 degrees, RA 10h 12m, Dec +22, which is about 2 degrees down to the right of the star zeta Leonis, the star called Adhafera. The radiant is an area, not just a point in the sky. In fact, with the Earth intersecting several dust trails this year, there will be slight differences in radiant position. A map showing the movement of the Leonid radiant over time can be found at http://www.imo.net/calendar/cal01.html#Leonids.

These are very fast meteors, with a velocity of about 71 km per second. Get comfortable in your lawnchair, and center your gaze about 50 degrees up in the sky. As these meteors are very fast, the fainter ones may be difficult to detect for beginning observers. If you concentrate on one direction in the sky, instead of moving all over, you will have a better chance of seeing more meteors, especially the fainter ones. And a dark country sky is important!

If you want to record your observations, see the NAMN Observing Guide for useful information, http://www.namnmeteors.org/guide.html. For practice, download Sirko Molauís meteor storm simulation at ftp://ftp.imo.net/pub/software/metsim/. For information on meteor photography, see http://www.imo.net/photo/index.html, and for video recording, see http://www.imo.net/video/index.html.

Published by permission from the North American Meteor Network (NAMN). For more information, see http://www.namnmeteors.org. Contacts: Mark Davis, coordinator, sc.meteors@home.com, Lew Gramer, Public Outreach, dedalus@alum.mit.edu, http://www.meteorobs.org.

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