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[OM] Re: [OT] lighting detector

Subject: [OM] Re: [OT] lighting detector
From: Marten Beels <mbeels@xxxxxxxxx>
Date: Tue, 18 Sep 2007 07:12:00 -0700 (PDT)

> Marten Beels <mbeels@xxxxxxxxx> wrote:
> 
> 
> I started reading a bit about lightning spectroscopy, and a few
sources
> indicated that lightning was a strong source of UV light, around 400
> nm.

I'm not surprised that a lightning strike would emit a fair amount of
 UV (+visible+IR+radio) as it's much like an electronic flash
(different
 gas composition though) not in a tube.  Did you find any images made
 from lightning in the UV range ?

...Wayne

Wayne Harridge

http://lrh.structuregraphs.com

I didn't find any UV images of lightning, but I did find some
interesting reading on lightning spectroscopy.  What I was really
wondering is what sort of "precursors" there might be.  What sort of
events (if any) happen before the visible flash?  What is the first
indicator that lightning is about to strike?  

If each re-strike of a lightning bolt are separated by approximately
40-50ms, and a camera has a delay of 130-160 ms, then there need to be
several re-strikes in order to catch one on film.

I did read that lightning typically has strong characteristic lines in
its spectrum due to N2 and H2, and that certain types of lightning,
like the "dart leader" has a slightly different signature of spectral
emissions.  

Lots of fascinating reading on lightning,

Marten


      
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