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    Re: Sextants with Polarizing filters
    From: Bill B
    Date: 2006 Jan 26, 01:24 -0500

    >> George
    >> Sorry you do not endorse my paraphrase ;-) Googled filters today, and
    >> a maker of fine optics, Schneider, used the same analogy (albeit a
    >> better explanation--a picket fence:
    Ken wrote
    > Bill,
    > If you have 3 polarizers you can easily see how the picket fence analogy
    > fails. Simply line up 2 filters with a space between them. Rotate one until
    > you
    > get maximum darkening (here the axes of polarization are at 90? to each
    > other). Now insert the 3rd polarizer in between the other two. Suddenly light
    > passes through all three! How could the middle polarizer change the
    > orientation of the other two "picket fences"?
    By some odd coincidence, there are three polarizing filters on my desk ;-)
    I tried your experiment.  Depending on the orientation of the (inserted)
    middle filter, it can reduce the light loss significantly.  Not being a
    believer in creating light without some form of energy being introduced into
    the system, or present energy becoming light, and having had no photographic
    reason to stack three filters, I am at a loss to explain.
    Please note I stated several areas of concern/areas for exploration
    regarding my thoughts on the topic. Added to that list, would the above
    experiment yield similar results if the filters did not have a space between
    Another portion of my message not quoted, "I am out of my depth on
    this one, not knowing the scale of light waves vs. openings and spacing of
    the openings.  Perhaps one of our physics mavens can address that?"
    One more question, Just how the h-ll can that work? Please elucidate me/us.

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