On Sun, 2009-08-09 at 13:24 -0400, Robert A. LaBudde wrote:
> I realized recently that I have no idea how an absolute measure of 
> radiant light power at even a single fixed wavelength can be made.
> 
> E.g., suppose you have an LED at 620 nm center frequency and you want 
> to measure power output. How do you do this?
> 
> It is easy enough to construct a detector system that gives a result 
> proportional to power, but how do you scale that measurement to 
> absolute radiance?

A while ago it was suggested that using the sun is a quick and dirty
way, assuming a clear sky it's supposedly pretty easy to get radiance
numbers. Only issue is how much brighter the sun is then most sources,
it might saturate your detector.

TTYL

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