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Aurigids outburst, predicted details:
When: 2007 September 1 at 04:15 a.m. PDT plus or minus 20 minutes, with a
main activity window of 30 minutes to either side of the peak time.
Where: The Pacific Northwest is ideally situated. Too far east or north would
put the peak time into daylight, or at least twilight. Too far south or west
would lower the radiant altitude in the sky, hiding many meteors. But areas in
the western U.S. States and Canadian Provinces down to Mexico and out to Hawaii
will be able to see at least some of this rare event.
About meteors: Meteor events, also called "shooting stars", are classified as
"sporadic" (unpredicted and no known association with a comet); "showers"
(annual, from streams that have diffused in space); "outbursts" (Earth passes
through a small or widely-spread stream); or "storms" (raresr events, when Earth
passes through a large, concentrated stream and produces more than 1000 meteors
per hour).
What is predicted: The Earth will pass through one of the streams from the
annual meteor shower named the "Aurigids" after the constellation the meteors
appear to come from, Auriga the Charioteer. That constellation contains the
bright star Capella, the third-brightest star in the northern skies. The
Aurigids previously made unpredicted appearances in 1935, 1986, and 1994. But
astronomers have now learned how to predict the origin and motions of these
invisible meteor streams through space. The origin is Comet Kiess, which last
appeared in 1911. And in 2007, the Earth will again pass directly through one of
the streams that escaped from the comet, producing a short-lived but intense
outburst of meteors. The duration will be an hour or less. The predicted peak
rate is 300 meteors per hour, uncertain by a factor of three. These will mostly
be brighter-than-average meteors, easily visible in a clear, dark sky away from
city lights.
Observing recommendations: The radiant will be high in the eastern sky when
viewed from Washington State. Meteors will travel in all directions, but their
paths will all trace back to the constellation Auriga. To see the most meteors,
recline on a blanket or in an easy chair so as to get a comfortable overhead
view. Meteors will originate from a point high in the eastern sky, but the Moon
will be in the southeast, so face away from the Moon or use an obstacle to block
direct moonlight from your eyes. Dress for very cool weather at that early
morning hour. Avoid or screen off artificial light sources. Conditions are
optimal if you can see the faint band of the Milky Way in the northwest despite
the moonlight.
For additional information, see
http://www.skyandtelescope.com/observing/home/9332696.html or "EOS,
Transactions , American Geophysical Union 98:317-318 (2007 Aug. 7).
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