Recent developments in space-borne zodiacal light photometry

The zodiacal light experiment to be flown aboard the International Solar Polar Mission in 1985 is presented. Overall objectives of the Zodiacal Light/Background Starlight Experiment include the study of the brightness, polarization, and color of the diffuse sky brightness and the determination of the spatial distributions and physical properties of the interplanetary dust as a function of spacecraft position in and out of the ecliptic. To meet these objectives, a multicolor sky-scanning photopolarimeter will be carried on the NASA spacecraft which will provide optimized stray light suppression and a capability for changing the viewing cone angle based on the use of a stepping device. Brightness and polarization measurements will be made for 11 center wavelengths in the UV and visible with 5.6 deg circular and 1.0 sq deg rectangular fields of view.