Wavelength Dependence of Polarization. XX. The Integrated Disk of the Moon

Photoelectric polarimetry of the whole lunar disk in eight wavelength intervals between 0.3 and 0.6 at a range of phase angles between 0 and 11400 I is presented. The observations were made near Tucson and in Hawaii, with a design-study model of a polarimeter for space missions. The polarization is maximum near + and 1000 phase angle, and it increases progressively with decreasing wavelength. The polarization maximum occurs at smaller phase angles for the longer wavelengths. There is no domain of negative polariza- tion near 1800 phase corresponding to the one near 0 phase. For phase angles greater than 14001 the electric-vector maximum is perpendicular to the scattering plane and there is no rotation of the plane of polarization within an accuracy of +20. Some excess polarization with the electric-vector maximum in the scattering plane has been found during certain eclipses.