From: whit3rd@gmail.com   
      
   On Tuesday, October 10, 2017 at 3:45:39 PM UTC-7, glen walpert wrote:   
   > On Mon, 09 Oct 2017 16:38:18 -0700, whit3rd wrote:   
   >   
   > > On Tuesday, October 3, 2017 at 6:55:37 PM UTC-7, malna...@gmail.com   
   > > wrote:   
   > >   
   > >> I am working...to measure the strength of the sunlight without   
   > >> introducing too much of a bias based on the time of the day - when the   
   > >> sun shines at a different angle   
      
   > > Well, the classical approach is to use a crystal ball, and a carved   
   > > wooden screen.   
      
   > Interesting approach, but for simple electronic monitoring with no moving   
   > parts how about the method used by photographic lightmeters for   
   > omnidirectional measurement, a spherical diffuser placed over the   
   > detector,   
      
   A good approach too, is an integrating sphere; basically, a white sphere   
   with a porthole, or (to get fancy) two spheres, with a porthole into the   
   first, and an aperture from the first to the second, with the sensor   
   in the second.   
      
   The weakness, is that the direction of the illumination can be   
   edge-on to the circular hole,  it isn't really as omnidirectional   
   as you'd like.   The hemisphere diffusers subtend pi *R*R as lit   
   from their axis of rotation, but only pi * R*R/2 if the source   
   is 90 degrees to that...   
      
   The angle dependence for a flat window is as cos(theta), so you   
   get 1% diminution after 8 degrees; a belt of hemispheres   
   at 16 degree intervals (22 sensors) and a choose-whichever-is-brightest   
   rule might do a good measurement job.   If you   
   need not only the plane of the ecliptic but the full 4pi steradians   
   covered, it's up to a couple of hundred sensors.   
      
   More practical, would be a couple of hundred light fibers, aimed all different   
   directions,   
   with end B coupled to a single, nonspherical plate of a sensor.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)