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"Robin M. Jensen" <[log in to unmask]>
Reply To:
Fri, 12 Nov 1999 07:59:23 -0800
text/plain (147 lines)
I know that the Rose City Astronomers here in Portland are having a "Star
at Rooster Rock State Park in the Columbia Gorge Wednesday, so the Leonid
should be visible to West coast residents as well (if our Oregon clouds
block the sky!)

Robin Jensen

Frank Ippolito wrote:

> Hey Folks,
> This just came through the museum pipeline. If things go as Mr Rao
> it might be worth stepping outside during the evening hours next
> Wednesday..........
> *******************************
> Of the dozen or so meteor showers per year, this particular one
> (called the "Leonids" and named for the constellation Leo from which
> its shooting stars appear to emanate) would not normally be worthy of
> comment except that its otherwise-unremarkable parent comet
> Tempel-Tuttle was just in the neighborhood.
> Comets are large balls of frozen, filthy ice. (Manhattan-size comets
> are not unusual.) When they near the Sun's heat in their elongated
> orbits they evaporate and lay a trail of detached dust particles
> behind them.  If the comet's orbit happens to cross Earth's orbit (as
> do the orbits of a dozen or so comets) then Earth plows through
> thousands of tons of their debris at relative speeds of 20 to 50
> miles per second.  The particles burn up in Earth's upper Atmosphere
> as their energy of motion converts to heat, creating incandescent
> streaks across the sky.
> But the closer Earth comes to the actual location of the comet in
> space the more significant the meteor shower is expected to be.
> Comet Tempel-Tuttle was recently where Earth will be Wednesday night.
> According to calculations performed by Hayden's own Joe Rao we have
> to believe that this year's Leonid meteor shower -- better termed a
> "storm" -- will brings thousands of shooting stars per hour, compared
> with its more tame annual average of 10 to 20 per hour.
> The Middle East will be best positioned for this display since its
> longitude lie on Earth's leading edge as we plow through the peak of
> the debris stream, but many of us are hopeful that some debris will
> be left over when the East Coast rotates into the path several hours
> later.
> Many satellites in orbit around Earth will be taking precautionary
> measures.  For example, the Hubble Space Telescope will be going into
> "safe-mode" during the passage, where the mirror's shutter closes
> down and the telescope orients so that its solar panels are parallel
> to the meteor stream rather than broadside to it.
> You needn't worry, however, as long as you don't go into orbit next
> I enclose Joe Rao's predictions below.
> ===============
> If the weather cooperates and skies are clear that night, millions of
> along the Eastern Seaboard of the United States may catch one of the
> meteor shower to occur in decades.
> A regular mid-November event, the Leonid meteor shower, could be extra
> good this year, perhaps even briefly attaining the status of a "meteor
> with shooting stars visible to the naked eye every few seconds.  Such a
> spectacle could develop as the Earth passes into a trail of dust-like
> left behind by the comet Tempel-Tuttle (the comet itself swept by the
> and Sun last year).
> But no one knows exactly how good any given meteor shower will be, even
> they expect the best.
> The peak of the Leonids should come  sometime between 9:08 and 11:17
> Eastern Time on Wednesday night.  During that time frame, he notes,
> the Earth will be sweeping within approximately  242,000 miles of
> the center of a cloud of debris that was shed by comet Tempel-Tuttle
> a century ago (in 1899).  If the meteor peak happens around
> 9:08 p.m., little or nothing of the expected meteor display would be
> since by Americans because the constellation of Leo - from which
> the meteors get their name - would still be below the horizon.
> But Leo begins to rise soon after 11 p.m.; hence if the peak comes
> later in the evening the odds would favor making quite a few meteor
>  From Europe and North Africa, some predictions are suggesting anywhere
> from many hundreds, to many thousands of meteors per hour, but nobody
> say with certainty just how many will be seen.
> Prospective meteor observers on this side of the Atlantic should
> carefully watch the sky, especially overhead and toward the northeast
> beginning anytime after 10 p.m.  The farther you are from the haze or
> pollution thrown off by big cities and towns, the better.
> Use a tilt-back chair at a site with a clear view of the sky.  Let your
> adjust to the darkness for about 15 minutes.  Lie back and gaze up at
> stars.  Every now and then a meteor will flit across the sky.  Faint
ones are
> tiny, quick streaks.  Brighter ones may sail across the heavens for
> seconds and leave a long-lasting glowing trail.  By dawn on Thursday
> - if you care to stay out that late - the constellation Leo will have
> high up toward the southern part of the sky.  By lying on your back, you
> see meteors occasionally shooting out of that area like spokes of a
> The Leonids move around the Sun in a direction opposite to that of the
>   Hence, they crash into our atmosphere head-on at speeds of up to 45
> per second.  They appear to the eye as darts or streaks of light.
> they can appear to silently explode in mid-flight, creating brighter
> of light.  Just the sight of one of these types of meteors will make the
> evening worthwhile.
> You just might need to see a few more metoers just to offset typically
> November  temperatures. Bundle-up! It's always best to watch a meteor
> with a companion -- shower with a friend!