luminous turbidity factor
quotient of the vertical optical thickness of a real turbid atmosphere and the vertical optical thickness of the pure and dry atmosphere (Rayleigh atmosphere), related to the visible part of the solar spectrum
Note 1 to entry: The luminous turbidity factor can be expressed by
Note 2 to entry: The luminous turbidity factor has unit one.
Note 3 to entry: This entry was numbered 17-743 in CIE S 017:2011.