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Generally, light might better be thought of as
elliptically polarized, having two components, one collinear with the major axis
and the collinear with the minor axis of the ellipse. If the the two axis are
equal, the light either randomly or circularly polarized and a polarizing
filter will have no effect. If the minor axis becomes
zero, the ellipse degenerates to a line and the light is said to
be linearly polarized and a polarizing filter will have maximum effect. The more
elliptically polarized the light, the greater the effect of the polarization
filter.
1. The (scattered
particle) light from certain portions of the sky becomes
(effectively) elliptically polarized by the effects of
varying refraction through varying (with
altitude) atmospheric density. The eccentricity of the polarized light
varies with path angles involved, specifically the angle(s) between the rays and
the normal to the atmospheric"layers". Polarization from reflection of
particles is essentially nil because the the particles are randomly
oriented.
2. Reflected light from a
reflective surface becomes elliptically polarized because the surface attenuates
the vertical component of the reflected light more than the horizontal
component. It is also angle dependent, that is, the lower the angle of incidence
the greater and more polarized the reflection.
Regards Bob... --------------------------------------------------------------- "I don't mind if you don't like my manners. I don't like them myself. They're pretty bad. I grieve over them long winter evenings." -- Philip Marlowe (Humphrey Bogart)
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