On Wednesday, May 21, 2014 11:24:44 AM UTC-4, gghe...@gmail.com wrote:   
   > Hi all,   
   >   
   > Well a question came up about measuring the solar constant.   
   >   
   > (how many watts/m**2)   
   >   
   > And I thought of measuring the short circuit current from a photodiode.   
   >   
   > But then you'd have to have some "fudge factor" that convolutes the   
   >   
   > PD responsivity with the solar spectrum.   
   >   
   > Does anyone have a good guess for the fudge factor?   
   >   
   >   
   >   
   > Say for a garden variety PD...   
   >   
   >   
   >   
   > Thanks   
   >   
   >   
   >   
   > George H.   
      
   It's worth mentioning that certain invisible wavelengths of the sun's spectrum   
   are important to monitor, as they play an inordinate role in human biology. 311   
    nm. is necessary for vitamin D production, and perhaps other things. This is   
   very variable, as this frequency is absorbed by the atmosphere.  I don't know   
   any detectors to assess this. How would that be done? A filter + PD?   
      
   jb   
      
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