(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

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

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
> ---
> Mailing list meteorobs
> meteorobs at meteorobs.org
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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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