Spectra Pritchard photometer

Spectra Pritchard photometer

[′spek·trə ′prich·ərd fə′täm·əd·ər]
(optics)
A photoelectric instrument for measuring the luminance of surfaces; it has a telescopic viewing system for imaging the bright surface to be measured on the cathode of a photoemissive tube, and a separate unit that combines the power supply with the controls and readout meter.