Definition: | quantity defined by the formula X where dΦp is the photon flux transmitted by an elementary beam passing through the given point and propagating in the solid angle dΩ containing the given direction; dA is the area of a section of that beam containing the given point; θ is the angle between the normal to that section and the direction of the beam
unit : s-1 • m-2 • sr-1
NOTE – See notes 1 to 5 to 845-01-34.
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