Calibration of spectral photometer to extra-terrestrial energy - using calibration factors obtained by diffusing disc and interchangeable wide angle lens

摘要

A calibration method and arrangement for illumination intensity and radiation density measurements are applicable to optical techniques, meteorology, and pref. remote reconnaissance of the ground. The method enables self-calibration of a spectral photometer to the extraterrestrial spectral energy distribution. The method does not require standard light sources and is used with a convenient spectral photometer design suitable for use in the field. The spectral photometer is calibrated w.r.t. the known extraterrestrial spectral energy distribution using a measurement aperture (6) and additional solar objective (1). Further measurements of extra-terrestrial energy distribution using the calibration factors obtained with the interchangeable calibrated solar objective are then performed successively with a diffusing disc (3) and interchangeable with angle objective (2). The dia. of the solar image is approximately half the dia. of the measurement aperture.