[meteorite-list] Perseid Meteors to Peak Late on the Night of August 11th

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Aug 10 11:16:42 2004
Message-ID: <200408101516.IAA19727_at_zagami.jpl.nasa.gov>

Sky & Telescope
Cambridge, Massachusetts

Contact:
Alan MacRobert, Senior Editor

Press Release: August 5, 2004

Perseid Meteors to Peak Late on the Night of August 11th

The Perseid meteor shower, an annual celestial event beloved by millions of
skywatchers around the world, returns to the night sky this coming week.

Sky & Telescope magazine predicts that the Perseid shower will reach its peak
late Wednesday night and early Thursday morning, August 11-12. The rate of
activity should pick up steam after midnight until the first light of dawn.
North America, especially the West and Hawaii, is optimally positioned to catch
the best of the shower.

An observer under a dark sky might typically see more than 60 Perseids per hour
between midnight and dawn. Since the waning crescent Moon will be only three
days from new at the time of shower maximum, posing minimal interference with
the view, this is an opportune year for watching them.

You'll need no equipment but your eyes. The darker your sky, the better - any
artificial light pollution in your sky will reduce the number of meteors that
are visible. But even if you live in an urban or suburban area, you have a good
chance of seeing at least some meteors. Find a dark spot with a wide-open view
of the sky. Bring a reclining lawn chair, insect repellent, and blankets or a
sleeping bag; clear August nights can get surprisingly chilly.

"Go out after about 11 p.m. or so, lie back, and watch the stars," says Sky &
Telescope senior editor Alan MacRobert. "Relax, be patient, and let your eyes
adapt to the dark. With a little luck you'll see a 'shooting star' every couple
of minutes on average."

Perseids can appear anywhere and everywhere in the sky. So the best direction to
watch is wherever your sky is darkest, probably straight up. Faint Perseids
appear as tiny, quick streaks. Occasional brighter ones may sail across the
heavens for several seconds and leave a brief train of glowing smoke.

If you trace each meteor's direction of flight backward far enough across the
sky, you'll find that your imaginary line crosses a spot in the constellation
Perseus, near Cassiopeia. This is the shower's radiant, the perspective point
from which all the Perseids would appear to come if you could see them
approaching from interplanetary space. The radiant is low in the north-northeast
before midnight and rises higher in the northeast during the early-morning hours.

Don't give up if it's cloudy Wednesday night. The Perseid shower lasts for about
two weeks, with good rates in the predawn hours of August 10th through 15th.
This year the ever-thinning Moon becomes less of a problem with each passing
night. Far fewer meteors will appear before midnight, even on the night of the
shower's maximum, because the radiant is then quite low in the sky. The radiant
is always low or below the horizon for Southern Hemisphere countries like
Australia, New Zealand, and South Africa, where few, if any, Perseids can be seen.

The Perseid meteoroids are tiny, sand- to pea-size bits of rocky debris that
were shed long ago by Comet Swift-Tuttle. This comet, like others, is slowly
disintegrating as it orbits the Sun. Over the centuries, its crumbly remains
have spread all along its 130-year orbit to form a sparse "river of rubble"
hundreds of millions of miles long.

Earth's own path around the Sun carries us through this stream of particles
every mid-August. The particles, or meteoroids, are traveling 37 miles per
second with respect to Earth at the place where we encounter them. So when one
of them strikes the upper atmosphere (about 50 to 80 miles up), it creates a
quick, white-hot streak of superheated air.

For several years in the early 1990s the Perseids performed spectacularly,
flaring with outbursts of up to hundreds of meteors per hour. The particles
responsible for these outbursts were probably shed during Comet Swift-Tuttle's
swing by the Sun in 1862.

Astronomers Esko Lyytinen of Finland and Tom Van Flandern of Washington, DC,
have alerted skygazers to the possibility that this "extra" Perseid peak could
make a comeback in 2004. They predict that this year, the rubble trail released
in 1862 will pass just 200,000 kilometers (125,000 miles)) inside Earth's orbit
on August 11th, just as observing conditions become optimal for meteor watchers
in Eastern Europe and eastern North Africa eastward to central Russia, India,
and western China.

Will the Perseids "storm" in 2004? There's only one way to find out: Get outside
and watch the show!

More about the Perseid meteors ? and how to watch and photograph them ? appears
in the August 2004 issue of Sky & Telescope magazine and online in the articles
listed at the end of this press release.

Sky Publishing Corp. was founded in 1941 by Charles A. Federer Jr. and Helen
Spence Federer, the original editors of Sky & Telescope magazine. The company's
headquarters are in Cambridge, Massachusetts, near the Harvard-Smithsonian
Center for Astrophysics. In addition to Sky & Telescope and SkyandTelescope.com,
the company publishes Night Sky magazine (a bimonthly for beginners with a Web
site at NightSkyMag.com), two annuals (Beautiful Universe and SkyWatch), as well
as books, star atlases, posters, prints, globes, and other fine astronomy products.

Related Articles:

* Meteors: A Primer
   http://skyandtelescope.com/observing/objects/meteors/article_91_1.asp
* Basics of Meteor Observing
   http://skyandtelescope.com/observing/objects/meteors/article_98_1.asp
* Advanced Meteor Observing
   http://skyandtelescope.com/observing/objects/meteors/article_102_1.asp
* The Discovery of the Perseid Meteors
   http://skyandtelescope.com/observing/objects/meteors/article_124_1.asp
* 2004: An Excellent Year for the Perseids
   http://skyandtelescope.com/observing/objects/meteors/article_1289_1.asp
Received on Tue 10 Aug 2004 11:16:39 AM PDT