We have developed a dual-field-of-view polarimetric spectral imager that can record polarization images in a full hemisphere or a narrow field, for looking at the polarization of skylight or a distant object, respectively. This effort is supported by the Air Force Office of Scientific Research. The instrument is deployed on a rooftop platform and collects data routinely through a wide range of conditions to study the variability of sky polarization as a function of cloud, aerosol, and underlying surface conditions.

DOP image

 

The Atmospheric Polarization Imager (API) uses an astronomical-grade CCD camera to view the entire sky dome through two liquid crystal variable retarders to achieve a full-Stokes image in only a few tenths of a second (important for imaging a scene with moving clouds). The system has a switchable fisheye or telephoto front end.

 All Sky