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Re: (meteorobs) Leonids in the news

In a message dated 10/11/00 1:27:33 PM Eastern Daylight Time, 
terry.johnson@rcenter.org writes:

<< I live in Tennessee (CST), and it looks to me like the times are going to
 fall on the nights of the 16/17 and 17/18 for me.  Will the drop-off of the
 rate be drastic enough to discourage me from observing on the night of the
 18/19th?  I was hoping make a public announcement of the shower and get
 about 50 people together for the show.

    If you're going to be out on the night of November 18/19, then shift your 
emphasis to the planets Jupiter and Saturn.  Both will be high up in the 
late-evening sky and will provide lots of "oohs" and "aahhs" from 
neophytes/beginners even in small telescopes.  So far as the Leonids are 
concerned, I wouldn't count on much more than 5 per hour at most in the 
after-midnight hours.  You are correct in your assumption that the heaviest 
activity is likely to occur on the two previous nights.  In the wake of their 
maximum activity, the Leonids tend to drop-off rather quickly.  In fact . . . 
Robert L. Hawkes in the Observer's Handbook 2000 of the RASC suggests that 
(nominally) the Leonids are only one-quarter of their peak strength just 0.5 
days (12 hours) after the peak.  Of course, there is always the hope of 
catching sight of a brilliant Leonid fireball among the late stragglers, but 
this is not too likely.    

Also, with a last-quarter moon in the midst of the action, what is the
expected visible rate if the ZHR is >100? >>

    Much will certainly depend on whether the majority of the visible meteors 
visible are relatively bright or faint.  A sudden outburst of a few hundred 
per hour can be very impressive, but with a Last Quarter Moon nearby to the 
radiant, this rate can be significantly reduced if the majority of the 
meteors are relatively faint.  Of the two potential nights with the promise 
of significant Leonid activity, I think (based on ejection values and that 
the meteor trails on the latter night are coming from inside the Earth's 
orbit) that the meteors will be brighter on the 17/18 as opposed to the 
16/17.  

-- joe rao
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