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Spectral samples at a distance- how do you tell what you're sampling?
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Shannon Dosemagen  
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 More options Apr 30 2012, 5:26 pm
From: Shannon Dosemagen <shannon.dosema...@gmail.com>
Date: Mon, 30 Apr 2012 21:26:08 +0000
Local: Mon, Apr 30 2012 5:26 pm
Subject: Spectral samples at a distance- how do you tell what you're sampling?

In Louisiana we're interested in using the spectrometer to look at
smokestacks from chemical plants/refineries and other potential "samples"
that are at a distance, such as an oil slick in the water from an airplane.
Thus far, I've only used the spectrometer to look at close-up samples, but
when talking to Scott Eustis, the question came up how we would actually
know what we are sampling from a distance? Thoughts?


 
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Eyal Saiet  
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 More options Apr 30 2012, 7:14 pm
From: Eyal Saiet <ejsa...@alaska.edu>
Date: Mon, 30 Apr 2012 15:14:58 -0800
Local: Mon, Apr 30 2012 7:14 pm
Subject: Re: [PLOTS] Spectral samples at a distance- how do you tell what you're sampling?

Hello,

This idea is applied today in instruments e.g DOAS (Deferential Optical
Absorption spectroscopy).

What is done is choosing  a window of interest say 335-345nm  acounting for
the absortion cross section for the specices likely to be present.

This is described in the  following paper:
http://hal-insu.archives-ouvertes.fr/hal-00295394/

This technique is great for molecules like not aerosols that have various
absorption cross sections based on the conglomeration stuff..
Eyal

On Mon, Apr 30, 2012 at 1:26 PM, Shannon Dosemagen <

shannon.dosema...@gmail.com> wrote:
> In Louisiana we're interested in using the spectrometer to look at
> smokestacks from chemical plants/refineries and other potential "samples"
> that are at a distance, such as an oil slick in the water from an airplane.
> Thus far, I've only used the spectrometer to look at close-up samples, but
> when talking to Scott Eustis, the question came up how we would actually
> know what we are sampling from a distance? Thoughts?

> -- Post to this group at publiclaboratory@googlegroups.com. To
> unsubscribe, email publiclaboratory+unsubscribe@googlegroups.com. Options
> at https://groups.google.com/d/forum/publiclaboratory?hl=en

--
Eyal Saiet

 
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Adam Griffith  
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 More options Apr 30 2012, 10:03 pm
From: Adam Griffith <adamdgriff...@gmail.com>
Date: Mon, 30 Apr 2012 22:03:32 -0400
Local: Mon, Apr 30 2012 10:03 pm
Subject: Re: [PLOTS] Spectral samples at a distance- how do you tell what you're sampling?

That's great info, Eyal.  Do you know what sort of spectral resolution in
required?  That is a fairly narrow window there of only 10 nm.

Adam

--
Adam Griffith
Director of Science and Coastal Environments
publiclaboratory.org
828.321.2326

 
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Jeffrey Warren  
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 More options May 2 2012, 3:47 pm
From: Jeffrey Warren <j...@publiclaboratory.org>
Date: Wed, 2 May 2012 15:47:30 -0400
Local: Wed, May 2 2012 3:47 pm
Subject: Re: [PLOTS] Spectral samples at a distance- how do you tell what you're sampling?

I think this may be a more basic question than Eyal is reading into it --
basically, it's like a gun sight -- how do you know you're aiming at the
right spot if you're 200 yards away? or a mile away?

I put up some sketches and ideas here:
http://publiclaboratory.org/notes/warren/5-1-2012/spectrometer-alignm...

based on looking through a drinking straw, carefully watching the overall
brightness in the Spectral Workbench client software, and noting when you
pass the spectrometer across a distant bright light.

i think we just have to try it out and see if something like this can work!

jeff

On Mon, Apr 30, 2012 at 10:03 PM, Adam Griffith <adamdgriff...@gmail.com>wrote:


 
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