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Re: (meteorobs) leonids storm



I just now joined this list, and have seen mention of the Leonid simulation
program a couple of times. Where could I get the program?

Robert

Hartwig Luethen (via Lew Gramer) wrote:

> [From Lew, the meteorobs list administrator: Please note Hartwig
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>
> Khaled M. Tell wrote today:
>
> > I have recently viewed the imo leonid meteor storm simulation(
> > metsim)and I was very much impressed with the program which was
> > carefully made and accurately simulating a meteor storm.
>
> Yes, Sirkos program is indeed very nice.
>
> > the program convinced me that I could not count that much of meteors if
> > the rate is over 10 meteors per second. ( which counts to  36000 meteors
> > / hour ). it seemed to me that the eye and the brain could not count and
> > even follow such high numbers of meteors. so the program left me
> > helpless.
>
> I completely agree that one cannot COUNT more than 5-6 meteors per second.
> Nevertheless one can roughly ESTIMATE such rates. Turn on metsim, simulate
> 10 meteors per second and the 50 meteors per second. There is a hige
> difference.
>
> What we found helpful was to open the eye for 1s intervals (or imagine 1s
> time intervals) and to guess or estimate how many meteors were seen in
> this interval. Averageing estimates from several intervals (one can do
> that roughly without calculation from time to time) will than yield
> something like a rate estimate (25/s, 50/s). The typical error was about
> 30% or even less. Sirko and I have published a paper in a recent issue of
> WGN.
>
> > moreover, I tried to test the method suggested by the imo, that is to
> > change to ten meteors count and replace them by one beep instead of
> > counting, but it appeared to me that this method is not practical to me
> > with the presence of high numbers of meteors.
>
> I think that method will work fine if you have a rate of, say, 1-2 meteors
> per second. Due to apparent statistical clustering the distribution will
> seem inhomogenous. So you will have e.g. 2-3 seconds without any meteor
> and then 4 meteors almost simultaneously. In such a situation this method
> may work very well. At  30 meteors per second this method will fail since
> it depends on accurate counting individual meteors, which is of course not
> possible.
>
> > moreover, in the sky, meteors will be distributed all over the sky
> > heading north, south, west, and east, so one may miss some meteors. but
> > in the program, one can see all meteors coming, although he can not
> > count them all.
>
> Yes. The observer will notice a larger percentage of faint meteors at the
> center of his field of vision than in the periphery, where he may only
> notice the really bright ones.
>
> However, ZHR is normally defined as a single observers4s rate, and of
> course any single observer will always only perceive only a fraction of
> the meteors present in the sky.
>
> You are right, of course, that one of the limitation of a simulation
> program is that it cannot actually simulate this aspect. However, the idea
> behind this program was to explore the capability of an observers to count
> or estimate correctly storm rates of meteors, and not to explore the
> characteristics of meteor perception in individual observers.
>
> So, lets hope that the Leonids will live up to the high expectations!
>
> Hartwig Luethen
>
> ------- End of Forwarded Message


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