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    What does it mean "tropicalized"?
    From: Alexandre Eremenko
    Date: 2014 Oct 24, 19:00 +0000

    It is well-known that SNO-T in the  Soviet sextant means:
    S - Sextant
    N - for Navigation
    O - with an illumination device ("Osvetitel")
    T - Tropicalized.
    What did they exactly mean by "tropicalized" ?
    I have only conjectures.
    1. Both SNO-M and SNO-T have the unique magnifier
    with luminous paint, so it works for illumination of the scales.
    The manuals say that the scales themselves are covered with this paint,
    but I don't believe them. It is the magnifier that is covered. Inside surface of it.
    They may have had some new paint composition on SNO-T to withstand high temperatures
    and humidity.
    2. SNO-M and SNO-T are radically different designs (the first one is the clone of C. Plath,
    the second of Freiberger). The most conspicuous feature of Freibergers and SNO-T is the 
    completely enclosed worm. Can this have something to do with "tropicalization"?
    To prevent some insects entering between the arc and the worm??
    I always thought thsat most of those tiny insects live in Canada and Soviet Arctic regions:-)
    What else could they mean?
    Does anyone know when Freiberger started to produce sextants?
    I have never seen pre WW II Freibergers.

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