There is a different idea that I would like to check. Knowing the Acuity Index, what’s the beam divergence angle estimate?
I cooked this formula (based on beam limits being FWHM intensity, Gaussian radial distribution within the beam, and f fraction of total lumens going into the beam which depends on 1 - spill angle and thus the h/D of the reflector):
beam divergence angle = [360/pi*sqrt(ln(2))*sqrt(f)]/Acuity_Index
If I fix f at around 0.8 for reflectors close to h/D=1, it simplifies to:
~85/Acuity_Index
Would it pass sanity test, I wonder?