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    Re: Restoration
    From: Brad Morris
    Date: 2018 Sep 21, 19:30 -0400
    Hi Tony

    I had my mirrors re slivered professionally.  It was reasonably inexpensive and the results were pure perfection.  Effortless too.

    If you intend to do it yourself, then to answer your question about film thickness:  it wont matter, unless it is too thin!! The reflective surface is against the glass.  Extra material does not affect that surface nor the image quality.   In front surface mirrors, the reflective surface is furthest from the glass, and thickness variations affect image quality.  

    Hope this helps

    On Fri, Sep 21, 2018, 6:10 PM Tony Oz <NoReply_TonyOz@fer3.com> wrote:


    Recently I got a C.-P.-based soviet sextant on a flee-market. Its' mirrors need re-silvering.

    All the info about the process relates to the DIY-astronomers silvering their DIY-mirrors - when they have to intricately polish the reflective surface because it is on top of the glass (rather than under it).

    Will I need the polishing step as well (and should I worry of an excessive silver layer thikness - which is a problem for DIY-astronomers because of the unwanted silver crystalisation)? The reflective layer on a sextant mirror is to be formed "underneath" the optically-flat glass.

    Or should I simply go the the reputable mirror shop for aluminium vacuum-coating?

    Please comment.

    Warm regards,


    60°N 30°E

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