Design and calibration of a portable spectroradiometer for the visible range (400-700 mu)

A spectroradiometer, consisting of 3 principal components, a monochrometer, a photoelectric detector, and a CD amplifier, has been designed for objective measurements of spectral light energy from natural and artificial sources in the visible (400 to 700 M..mu..) range. It is calibrated as a secondary measuring device by using a tungsten filament lamp which, in turn, is calibrated by a primary standard for color temperature, and luminous intensity. Principal limitations of the spectroradiometer are that measurements are confined to the visible spectrum, and accuracy within the red region is limited for fluorescent type lamps. Correction factors are also necessary when the instrument is used for measuring spectral and total irradiances from a light source other than a point or distant one. 20 references, 4 figures, 5 tables.