Observational Technique: Imaging Polarimetry Using Double Refraction

An optically corrected calcite prism produces double polarized images which can be analyzed by aperture photometry to give the polarization of each object in the field.
Errors from seeing and transparency variations vanish since they affect both images equally.

An optically corrected calcite prism produces double polarized images which can be analyzed by aperture photometry to give the polarization of each object in the field.