Perseids 2001
More information on the Perseids:
Space Weather News for August 14, 2001
PERSEID METEORS
The 2001 Perseid meteor shower peaked on Sunday, August
12th. In case you missed the show, visit our Perseid meteor gallery,
which includes a unique movie of a Perseid meteor streaking over the
Marshall Space Flight Center. The movie's sound track is the meteor's
eerie-sounding radar echo.
ROCKET DECAY
One of the most dazzling sites of the 2001 Perseid meteor
shower wasn't a Perseid at all. A piece of a Russian rocket fell to Earth
over the Atlantic ocean on August 12th, passing first over Maine and
eastern Canada. The disintegrating rocket shell created a dazzling
fireball. See the pictures on SpaceWeather.com!
SPACE.com Weekend Edition:
Perseids Meteor Showers Viewer's Guide
The reliable Perseids are a do-not-miss event. SPACE.com's editors
encourage you to go out and look up this weekend.
Space Weather News for August 10, 2001
PERSEID WEEKEND
The annual Perseid meteor shower will climax this weekend on
August 12th. Tune into spaceweather.com for observing tips, live meteor
radar echoes, images of the shower and more....
2001 August 07
Perseid Display
Here's an early warning and observing notes for the upcoming annual
Perseid meteor shower, traditionally one of the best. Although the maximum is
reached the night of August 11-12 this year, a few nights on either side
usually have increased numbers of meteors.
Most meteors are very small, from the size of sand grains to pea-sized. However, when they run into the thin upper atmosphere of Earth, they're travelling at 12-15,000 miles per hour, heat to incandescence, and turn into dust. Even though they are small, their incandescence is so bright we can see them from the surface, miles below. The particles are not "burning," which is an oxidation reaction, but are mechanically heated by friction with air molecules, mostly nitrogen. A very few meteors may be bigger, even up to a sensible diameter you can perceive. You're lucky if you see one! Even more rare would be a fireball type. Many years ago I witnessed a so-called "green fireball" which appeared larger than the full Moon, left a glowing trail, and seemed to disappear suddenly, like a light going out. Haven't seen one since. I suspect it was some sort of ice rather than a rock.
Regular, predictable meteor showers such as the Perseids happen when Earth in its orbit intersects the elongated orbit of a comet. Ice and rock from the parent comet are expelled when the comet is near the Sun, making the comet's tail, and this material spreads out over the total orbital track of the comet. If memory serves, the Perseids have been linked to Comet Swift-Tuttle. So we're getting material from the far reaches of the Solar System, either the Kuiper belt or the Oort Cloud, depending on the associated comet.
Very, very few meteors reach the ground. The chances are so small of one landing anywhere that could be dangerous to any given observer, such as yourself, are too small to bother computing. So don't worry, hope for clear skies, and enjoy the show!
Bryce Walden,
Oregon L5 Society, Inc.
2001 August 07
AstroAlert: Another Moonlit Perseid Display
The annual Perseid meteor shower will reach maximum activity Sunday
morning August 12. Like last year the moon will be in the sky reducing
the number of meteors seen. Last year there was an small opportunity
late in the morning to view the Perseids in a dark sky once the moon
set. Observers who watched during this period remarked that the display
was far richer than that seen in 1999 despite a bright aurora display.
This year the moon free period lies between dusk and moonrise on
Saturday August 11. This time will be approximately 9 pm local daylight
time (2100) and midnight depending on your location. At this time of
night the Perseid radiant, the area of the sky the meteors seem to come
from, will lie low in the northern sky. For the Southern Hemisphere and
north tropical areas it will actually be located below the horizon and
no activity can be seen from there until later in the night. With the
radiant lying so low in the sky from north temperate areas the horizon
will block a great majority of the Perseid activity. The Perseids that
do travel upwards will just be skimming the upper regions of the
atmosphere allowing them to last several seconds and create a long
streak across the sky. These "earthgrazers" are exciting to see but are
only seen once or twice per hour.
The the night progresses the Perseid radiant will rise higher into the northeastern sky. Those living in high northern latitudes have the advantage of the radiant being located higher in their sky. Unfortunately morning twilight will also arrive earlier for them cutting short their show. North tropical and north temperate latitudes are best suited to see the display with the lower radiant altitudes being offset by a longer night as one proceeds southward. As one approaches the equator the Perseid radiant does not rise much higher than 30 degrees before morning twilight interferes. This again limits the amount of activity seen. It gets worse as one travels past the equator into the Southern Hemisphere. From 30 degrees south the radiant rises only 3 degrees high so the best observers in Australia, South Africa, and southern South America can expect is 2-3 Perseids per hour.
What can mid northern latitude observers expect to see this year? Since there will be moonlight in the morning sky it definitely will not be as impressive as the 2000 display. Activity will increase as the night progresses as the radiant rises higher into the sky. The moon will rise around midnight and will be located high in the southeastern sky during the last dark hour before morning twilight. This last dark hour before morning twilight (approximately 4 to 5am on August 12) will offer the most activity. To offset the bright moonlight it would be advisable to face away from the moon toward the north or northwest. One should look high enough into the sky so that the bottom of their field of view is not wasted on the ground. This means that most people should view 60-70 degrees high (90 being straight up). In similar circumstances in 1982 I was able to count up to 38 Perseids per hour from a rural observing site. Those who watch from urban areas or experience hazy skies will see less activity.
Meteor photography is also possible if you aim the camera far away from the moon. Use slow to medium speed film such as ISO 100 to 400. A manual single lens reflex camera is necessary as you need to keep the shutter open for 5-10 minutes. Aim the camera so that the bottom of the frame lies just above the horizon. A good direction to aim would be due north as the star trails are least in this direction. The stars will show parallel paths on your photo. Any meteor caught on film will cross these paths and will be easy to find. A meteor must be as bright as the brightest stars to be recorded on film. Even during the Perseids the rate of success averages only 1 meteor per roll of 24 exposures. It's all a matter of luck! Advanced meteor photographers often use a motor driven mount to prevent the stars from trailing in their photos. Therefore any streak on the photo could be a meteor or a man-made satellite.
Sky & Telescope, the AMS, and the International Meteor Organization are
interested in your Perseid counts. The basic information needed is your
location, the time you watched, the number of Perseids seen, the number
of other meteors seen, and the sky conditions (clouds, limiting
magnitude). You may also try to estimate the brightness of each meteor
by comparing it to stars of a known magnitude. Reports can be sent to me
at:
lunro.imo.usa@home.com
and to Sky & Telescope at:
observers@skypub.com
For more information on observing meteors visit the Sky & Telescope Web Pages at: http://www.skypub.com/sights/meteors/meteorwatch.html Although intended primarily for the Leonid meteor shower, this guide is useful for all meteor observing sessions.
A weekly preview of meteor activity is also published each Thursday at: http://www.amsmeteors.org/lunsford/">
Clear Skies!
Robert Lunsford
Secretary General of the International Meteor Organization
Visual Meteor Program Coordinator of the American Meteor Society
What's New on Thursday's Classroom:
August 4, 2001
THE PERSEID METEOR SHOWER
The annual Perseid meteor shower peaks this
year on August 12th. Get your students ready for the shower with the
kid's story "Catch a Shooting Star." Lessons include Sky Orienteering to
find the Perseid radiant, a meteor coloring book, and reading lessons that
reveal the differences between meteors, meteoroids, and their parents --
comets. Even better, whip up some Falling Star French Toast for a long
night of observing!
PERSEÏDEN
Zondagochtend 12 augustus om 08 u. en 's avonds om 21 u. zijn er twee maxima
van de Perseïden: een meteorenzwerm waarvan de radiant (het vluchtpunt van waaruit de
meteoren lijken weg te schieten aan de hemel) gelegen is in het sterrenbeeld Perseus.
Omdat op beide tijdstippen de zon al op is, kunnen de Perseïden het best worden bekeken in de nacht van 11/12 en de nacht van 12/13 augustus. Begin met waarnemen vanaf omstreeks 22 u., het einde van de burgerlijke schemering. Na omstreeks 02.30 u. zal het maanlicht in toenemende mate gaan storen.
De afgelopen jaren waren tijdens het maximum zo'n 150 - 400 meteoren per uur te zien. Overigens zijn de Perseïden een aantal weken actief, van omstreeks 15 juli tot 20 augustus.
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