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    Re: Sextant mirrors
    From: Fred Hebard
    Date: 2007 Oct 8, 21:05 -0400

    Some sextant mirrors have the reflective surface on the front, but,
    traditionally, they've been on the back, I suppose in order to
    protect the reflector; they allow coating of the back and sides with
    salt- and water-resistant materials.  Yes, rear-coated mirrors give
    multiple images, but they are easy to distinguish.
    
    
    On Oct 8, 2007, at 8:54 PM, Jim wrote:
    
    >
    > Issue 96 of the Nav.Found,newsletter has an article concerning
    > mirrors.In which the author suggests that in an emergency the mirrors
    > may be replaced,using any type of mirror available e.g.vanity,hand
    > etc.It is my understanding that sextant mirrors are manufactured from
    > an optically flat material,which to me means that not only the two
    > sufaces be  flat but,also the refractive index.Is this correct.I have
    > read that using ordinary glass results in multiple images.
    >                             Jim Martin.
    >
    >
    > >
    
    
    
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