unit brightness
1.The unit of brightness in the centimeter-gram-second system, equivalent to the brightness of a perfectly diffusing surface that emits or reflects one lumen per square centimeter.
2.A unit of illuminative brightness equal to one candle per square meter, measured perpendicular to the rays of the source.
3.a cgs unit of illumination equal to the brightness of a perfectly diffusing surface that emits or reflects one lumen per square centimeter.
4.The degree of brightness of a celestial body designated on a numerical scale, on which the brightest star has magnitude-1.4 and the faintest visible star has magnitude6, with the scale rule such that a decrease of one unit represents an increase in apparent brightness by a factor of2.512.
5.A unit of retinal illumination, equal to the amount of light that reaches the retina through 1 square millimeter of pupil area from a surface having a brightness of 1 candela per square meter.
