A faint polarization pattern visible to the human eye when viewing an evenly illuminated surface, such as a cloud or the sky. Not detectable by everyone, it normally consists of a yellowish hourglass-shaped region with two circular blue regions on each side of the waist. The long axis of the yellow area is at right angles to the light's plane of vibration. The figure arises because of dichroism (differences in the colour absorbed depending on the plane of polarization) in the region of the retina known as the macula lutea. See also polarization of the sky.
Subjects: Meteorology and Climatology.