NOTE: This definition was changed in RP-16-17 Addendum 4. Deletions have a strike-through. New text is bold.
Quantity involved in the visual observation of a source of light when viewed directly from such a distance that the apparent diameter is inappreciable. The point brilliance is measured by the illuminance produced by the source on a plane that is at the observer’s eye and normal to the direction of the source.
(See also Allard’s law.)« Back to Definitions Index