From: rrllff@yahoo.com   
      
   On Thursday, May 29, 2014 8:08:07 AM UTC-4, haitic...@gmail.com wrote:   
   >   
   > 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   
      
   That's why a bolometer may be the best instrument.   
   Conceptually it can capture all wavelengths.  Very simply   
   one could have an absorber that covers the whole spectrum   
   (easier said than done, but not impossible) and measure   
   temperature changes.  The real work is in the details.   
      
   http://www.richardfisher.com   
      
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