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Re: (meteorobs) ZHR discrepancies?
Hi Mike,
> So how can we be seeing ZHR's varying by a factor of 5 at the same times for different observers? Is it possible the microstructure of the stream varies so much over different locations? The time spans of the observations seem too long for that. It could just be individual perception rates of the observers, of course, especially at the fainter end. But a factor of 5 is hard to explain even this way.
>
The scatter in visual observations is really large. A factor of five
is what I typically encounter in a global shower analysis. So the
question is: is the average something useful? On several occasions
I tried to calibrate observers according to their preception
characteristics, and averaged then. The result was amazingly close
to the first brutal average. This shows that -- if only the number
of people participating -- is large enough (>10 at the same time),
the average balances systematic deviations of individuals quite well.
And yes, there can also be local variations in the stream such as
with the Leonids 1999. Will be interesting to watch out for such
features in the 2001 storms. First, all the huge amounts of data
need to be entered. Who helps...?
Best wishes,
Rainer
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