(meteorobs) Video versus visual: my poster for the IMC
Marco Langbroek
marco.langbroek at wanadoo.nl
Wed Sep 14 11:46:16 EDT 2005
Hi Daniel,
A very interesting - and very important- study.
Two things that are perhaps obvious to remark (and indeed you do) are:
- how to account for the limiting magnitude/sky brightness variation
(the V-shape might be simply related to sun altitude below the horizon);
- variations with distance to radiant (indeed, you already mention this),
as imaging probability is also a function of angular speed.
Two perhaps less obvious, but I think valid ones to ponder:
- did you take into account the potential influence of the standard deviations
of your video ZHR data (and visual ZHR) on the ratio plot results?
(sigma = ZHR/sqrt(n)). As it are two datasets with not to be ignored standard
devations you compare, the effect is cumulative.
- variations in r-value might be a big problem. The camera is bound to be less
sensitive for fainter meteors. Which means that for fainter r-values, the
ratio visual-video ZHR wil be different than for brighter r-values, as the
latter has a more complete coverage. That is a problem when comparing
different streams, but also when the r-value fluctuates over the night for
one and the same stream.
Hope these comments are useful to you. These studies imho are very worthwhile.
- Marco
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Dr Marco Langbroek - Dutch Meteor Society (DMS)
e-mail: meteorites at dmsweb.org
DMS website: http://www.dmsweb.org
private website: http://home.wanadoo.nl/marco.langbroek
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Daniel Fischer wrote:
> At http://www.astro.uni-bonn.de/~dfischer/mintron/perseids.html the poster I've
> just prepared for the IMC in Belgium is open for discussion - input even from
> non-attendees of the conference (how dare you :-) could be worked into the
> version that goes into the printed proceedings.
>
> Daniel
> ---
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>
--
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Dr Marco Langbroek
Dutch Meteor Society (DMS)
e-mail: meteorites at dmsweb.org
private website http://home.wanadoo.nl/marco.langbroek
DMS website http://www.dmsweb.org
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