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Re: [leo2001] Re: (meteorobs) Leonid rate predictor URL




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To: leo2001@yahoogroups.com
From: Sirko Molau <molau@informatik.rwth-aachendot de>
Date: Wed, 8 Aug 2001 09:25:16 +0200 (CEST)
Subject: Re: [leo2001] Re:  (meteorobs) Leonid rate predictor URL


> > P.S.: Here's yet another intriguing item from the conference. A group
> > of Japanese amateurs has seen a dozen or so daylight meteors during
> > the Leonids storm peak of 1999 - and, assuming a limiting magnitude of
> > -4, calculated a ZHR of 4000. 

This ZHR value has nothing to do with reality. Remember that the ZHR
formulae has a term r^(6.5-lm). In this case they assumed r=1.6 (which was
derived on much fainter meteors and does not necessarily reflect the
brightness distribution of daylight fireballs) and the exponent was 10.5
(assuming an daylight lm of -4 mag). So the error bars are extremely large
and all you can say is probably just the order of magnitude of ZHR, i.e.
if it was 10^3, 10^4 or 10^5. I've been discussing this with the
authors of the poster yesterday. Still I find the idea interesting to try
to observe daylight fireballs during a storm.

> This web page mentions video observations of night time showers, during day.
> I assume there would be no problem setting up MetRec (automatic meteor
> detection from video) during the night and let it run throughout the
> day.  It would detect daylight fireballs, do the astrometry, and correctly
> attribute to known showers.  The assumption here, of course, is that the
> video system has automatic gain and that the Sun doesn't pass through the
> field!  There would likely be problems with birds, aircraft, pollen etc.
> It might also be interesting to detect some of the daytime meteor
> showers, like the beta Taurids.

It's certainly possible and worth a try to run MetRec for daylight
observations. However, I would definitely *not* use an image-intensified
camera, but an ordinary CCD video camera for this type of observations.
Just to make sure that nobody wrecks his intensifier tube. :-)

Sirko

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