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November 22, 1999: The 1999 Leonid meteor storm was
spectacular over Europe and parts of the Middle East where as
many as 70 meteors
per minute were seen by sky watchers. Meteor enthusiasts were spellbound by the display.
In North America most observers had a different story to tell. By the time the constellation Leo rose above the horizon in the United States, the storm was over. Only 20 to 40 meteors per hour were seen in most areas. Right: These four video frames captured by David Dunham, president of the International Occultation Timing Association, may be the first recorded evidence of a meteorite striking the moon. At peak brightness, the flash was about 3rd magnitude. [more information] Nevertheless, the most exciting Leonid observation may have occurred where the shower was weakest -- right here in the United States. Brian Cudnik, a research technician at Rice University and Prairie View A&M University, was watching the Moon for signs of flashes caused by Leonids striking the lunar surface. At about 4h 46m 20s UT on November 18 he saw a brief flash near the center of the Moon's dark side, close to the edge of the lunar disk. Observing with a 36cm telescope, he estimated that the flash, taking a fraction of a second, was at least as bright as a nearby 4th-magnitude star. Cudnik is an experienced observer of occultations, and he immediately contacted David Dunham, president of the International Occultation Timing Association for possible confirmation.
"I confirmed the observation in a video recording that I made using a 13cm telescope in Mount Airy, Maryland," says Dunham, who is also the chief of the mission design team for NASA's Near-Earth Asteroid Rendezvous (NEAR) mission. "The event occurred at a cusp angle of around 75 - 80N (10 to 15 deg. north of the lunar equator) 1.7' from the Moon's edge. The flash, timed from the videotape at 4h 46m 15s UT, is visible in only two video frames, the first at about 3rd magnitude and the second at about 8th magnitude." The images can be viewed at http://iota.jhuapl.edu/. "The object was probably a Leonid since the peak of this year's display was at 2h UT as seen from the Earth," continued Dunham. "The trailing Moon would arrive at the same solar longitude about 3h later, near the time of the observed impact. I also recorded 5 lunar occultations of 8th-magnitude stars an hour before the impact. Analysis of those images and others will permit a reasonably good determination of the brightness and location of the impact flash." Dunham has issued a call for other lunar observers to report data that might confirm his observation. Several groups have already reported in, he says, but so far everyone was looking at the wrong time or at the wrong spot. If you have video or visual observations of the Moon bearing evidence of possible Leonid meteorite impacts, please contact David Dunham at david.dunham@jhuapl.edu. |
Web Links |
Leonids Live! -site of the live webcast of the 1999 Leonids North American Meteor Network - home page Related Stories: Perseids
Live! Balloon Flight Planned
-- Aug 6, 1999. A NASA weather balloon will ascend to the stratosphere
for a live webcast of the 1999 Perseids. |
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