[Meteor-Scatter] Fwd: Joe Rao's summation of the 2002 Leonids

[Shelby Ennis, W8WN]

Here is Joe Rao's summary of the North American (second) peak of the 2002 
Leonids.
Remember that smaller particles not only produce less light, but less 
ionization for propagating radio signals.  Therefore, his summary seems to 
fit with what most of us heard (or didn't hear).

I don't have many visual reports on the earlier peak over Europe.  While it 
probably had fewer meteors, they appear to have been larger.  Radio reports 
indicate a poorer shower than last year, but better than we experienced in 
NA.  A number of European reports of 50+ contacts have been received.

Watch for updates on the Hot News page.
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>From: Skywayinc@aol.com
>Date: Thu, 21 Nov 2002 11:54:33 EST
>Subject: Joe Rao's summation of the 2002 Leonids
>
>     I've exchanged a few e-mails with Kelly Beatty and Roger Sinnott of S&T
>over the past 24 hours concerning the performance of this year's Leonids.
>Here in a nutshell is my "take" on what happened:
>
>LEONIDS 2002
>
>     The four-revolution dust trail of Comet 55P/Tempel-Tuttle was somewhat
>late in encountering the Earth on Tuesday morning, November 19.  Revised
>predictions by Rob McNaught and David Asher gave 10:34 UT as the time of the
>peak.  Esko Lyytinen and Ton Van Flandern forecast the peak for 10:40 UT.  It
>appears that the peak actually came within a minute of 10:48 UT, or 8 to 14
>minutes later than expected.
>
>     Interestingly . . . a prediction issued only several weeks earlier by
>Jeremie Vaubaillon, at the Inst. de Mecanique Celeste et de Calcul des
>Ephemerides (France), indicated that the 4-rev. peak would arrive at 10:47 UT
>-- apparently just one minute earlier than what actually happened!
>
>     The four revolution trail apparently consisted chiefly of very small
>particles which produced a meteor display much fainter than what was observed
>with this same trail in 2002.  There were far fewer fireballs and bolides
>reported in 2002 and it appears that many of the meteors were of second and
>third magnitude.  This sharp peak apparently lasted no more than 15 to 20
>minutes in duration, centered on 10:48 UT.
>
>     As such . . . moonlight, radiant altitude, local sky conditions and
>twilight all played key roles in what observers saw . . . or did not see.
>
>     Those blessed with excellent seeing and transparency conditions, along
>with a very high radiant position and with the moon low in the west and
>little or no twilight to contend with, saw a burst of 10 to 20 Leonids per
>minute (on average). I've received many such reports from the Carolinas down
>through Florida of people seeing just such a Leonid display.
>
>     Along other parts of the US East Coast, a scattered-to-broken layer of
>mid-to-high level cloudiness likely obscured a number of the fainter streaks.
>  Also, in other parts of the country, similar adverse sky conditions
>(combined with the bright moonlight) cut in significantly to the overall
>numbers that were seen.
>
>     In addition, the 8 to 14 minute delay in the predicted peak time meant
>that twilight conditions had advanced enough over the East Coast of the US,
>to allow the sky to brighten -- in some cases, as in the Northeast States --
>to a considerable degree.  As a result, many of the fainter meteors were lost
>in the brightening dawn glow.  Those who had to deal with such weather
>problems, as well as the increased twilight effects, probably came away
>feeling that the "big meteor shower" that had been heavily promoted in the
>media never came off!
>
>     In reality, however, the Leonids pretty much came off as anticipated.
>During the 15 to 20 minute peak, those observing with very favorable
>conditions saw meteors falling at the rate of 600 to 1200 per hour!
>
>     Again, the only drawback was the fact that many of the meteors were
>relatively faint . . . at least compared to the dazzlers that were observed
>in 2001!
>
>     Those who heard reports in their local media that " . . . up to 6,000
>meteors per hour" would be visible with this year's Leonids, did not listen
>carefully enough to the disclaimer (if it was mentioned at all) regarding the
>nearly full Moon; and that almost certainly only a fraction of those promised
>high rates would be visible thanks to the brilliant moonlight!  This factor
>was stressed several times in my Leonid article in the November 2002 S&T.
>
>     While a number of people saw an excellent Leonid show, the numbers of
>those who were disappointed or dissatisfied (or just downright angry) seem
>(at least to me) to be much larger.  Hell . . . even David Letterman
>complained ("Any of you guys wake up to see that big meteor storm they were
>predicting?; Well . . . I fell for it too.")
>
>     Yet, when the final analysis of this year's display are made 
> available by
>the IMO, I would not be the least bit surprised to hear that the final ZHR
>tally (after all the suitable "corrections" are made) will be somewhere in
>the 2,000 to 5,000 range.
>
>     No doubt, this will go down in astronomy annals as "The Leonid Meteor
>Storm that almost nobody saw!"
>
>-- joe rao

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