Measurements with a Spectral Radiometer*

Abstract

An ƒ/2.5 spectral radiometer, consisting of telescope and monochromator mounted on a movable head, is described. By comparison with a blackbody standard and appropriate calibration, spectral radiances can be obtained in watts/cm2-micron-steradian. Observation on many targets indicates a nearly identical radiance for all. Space scans at a given wavelength do give target distinguishability however, and a discussion of possible cause is given. Rapid variations in radiance have been observed, and are still being investigated.