Bidirectional reflectance spectroscopy. II - Experiments and observations

Aspects of the theoretical bidirectional reflectance expression derived by Hapke (1981) are studied experimentally, and it is shown that the expression describes satisfactorily the measured angular scattering and spectral properties of a cobalt glass powder in which the two properties vary greatly with wavelength. The theoretical reflectance function also describes measured distributions of intensity across the surfaces of planets, except near the sunlit limb, where the macroscopic roughness influences the brightness.