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Re: (meteorobs) Re: Opik
On Fri, 19 Apr 2002, Jeremie VAUBAILLON wrote:
> what to think of reported ZHR=~ 50000 in 1833 (Brown 1999, Icarus 138) ??
>
> Does this contradiction comes from the fact that this rate is deduced
> from a duration of observation of only 15 min maximum ?
Hi,
Peter Brown's estimate for 1833 was rather limited by the existing
observational "data". I suspect the peak rate would be VERY high for two
reasons additional to the existing counts.
1) People (including Olmstead) reported the sky light shining through the
window being bright, like moonlight. The integrated light of the meteors
must have been of the order of mag -8 or brighter. If a reasonable magnitude
index can be derived for 1833, one can estimate the necessary rate to give
an integrated flux of that brightness. (Need to include Leonid duration
vs mag for that radiant elevation, and instantaneous flux incorporating
themeteor durations).
2) Predictions of the time of maximum are probably more reliable than the
peak time Peter Brown derived from the very poor quality and limited
observational data. These predictions put maximum some 45 mins after
Brown's estimate and well into morning twilight from the eastern states
where most observations were made. The Indian tribes further west probably
had an even more stupendous show, perhaps consistent with their tales
of the shower.
Cheers, Rob
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