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    Re: Sextants with Polarizing filters
    From: Ken Muldrew
    Date: 2006 Jan 26, 09:19 -0700

    On 26 Jan 2006 at 1:24, Bill wrote:
    > One more question, Just how the h-ll can that work? Please elucidate me/us.
    I don't know of a good mechanical analogy other than to just state that
    the polarizer introduced inbetween the crossed polarizers (which is
    oriented so that it's not at 90? to either of the others) rotates the
    plane of polarization so that it's no longer at 90? when it now hits the
    3rd polarizer, so some light passes through. To see how this happens you
    really have to do the math. I guess the important part to consider is that
    light is an electromagnetic wave (i.e. there is an electric component and
    a magnetic component) so it is a mistake to just consider the electric
    component that passes through the first polarizer as being confined to a
    bunch of parallel planes. There is also the magnetic component which is
    orthogonal so it's better to think of the two components together. It's
    the interaction of this complex with the oblique polarizer in the center
    that rotates the plane of polarization away from the original orientation.
    I'm afraid there's just no good way to think of light in terms of objects
    with which we are familiar. Even the phycisist Richard Feynman, who knew
    as much about light as anyone, visualized light as invisible angels.
    Ken Muldrew.

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