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Re: (meteorobs) We are having fun now...

Hi Jim,
when I spoke about the problems there are with 'non-standard' data beeing 
difficult to analyze I was not refering to the AMS archive.
As I said, it was kind of a general statement. How could I 'judge' about
your data without even knowing it? :-))
 
> don't know what else you need for analysis.  Here is where you can educate
> me, what is the "brightness distribution"?  Is that the little chart each
> observer fills in with the numbers of meteors of different brightnesses?  If

Exactly, that's what I was talking about.
You need this table in order to determine the population index r of a
meteor shower. This may sound a little complicated, but is quite
straightforward: r simply expresses the ratio between bright and faint
meteors. If you have an r of, say, 3 (as sporadic meteors, for example)
you know, that there are 3 times more meteors of magnitude n+1 than of
magnitude n. This does not mean, that you actually see three times
more meteors (because the fainter the meteors the more you will miss), but
this value is essential if you want relate your observation to the
limiting magnitude standard 6.5 mag.
Unfortunately, r is varies for different showers and is not even constant
for a single meteor shower. Quite often you find a minimum of r-values
near the maximum of a shower. That is, at the maximum time you have an
excess of bright meteors. This is why it is neccessary to determine the
actual r value for the meteor shower at the given time you want to
investigate it.
Just an example: If you observe under non-optimal conditions you will
still see all the bright meteors. However, if you take a standard r value
from a book which is too big, you will come up with astronomical ZHR
values: You extrapolate that there must have been plenty of faint meteors
which simply weren't there...
Sirko

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*           Sirko Molau             *                    __              *  
*          Str.246 Nr.16            *             " 2B v 2B "            * 
*          D-13086 Berlin           *                                    * 
*        sirko.molau@dlrdot de         *                       Shakespeare  *
*      http://www.snafudot de/~smo     *                                    *
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