title: Polarization characteristics of an altazimuth sky scanner.
abstract: A theoretical description of the polarization characteristics of an altazimuth sky scanner optical system is presented based on Mueller-Stokes calculus. The theoretical results are verified experimentally. This unique computer-driven optical system was designed to perform laboratory studies of skylight as well as celestial objects during day or night and has the advantage that there are no space or weight limitations in the use of additional apparatus. The two parallel 45 degrees tilt mirrors that bring the light from any point of the sky down to the laboratory introduce some amount of intrinsic polarization, however. For that reason proper interpretation of the raw data requires a theoretical understanding of the polarization features of the instrument and accurate experimental determination of the elements of the Mueller-Stokes matrix describing the polarizing and depolarizing action of the system. This is especially true in the case of skylight intensity and polarization studies. A comparison of the theoretical and experimental results is given with an indication of the possible reasons for slight differences found between them.
authors.forename: L M
authors.initials: LM
authors.lastname: Garrison
authors.forename: Z
authors.initials: Z
authors.lastname: Blaszczak
authors.forename: A E
authors.initials: AE
authors.lastname: Green