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    Re: Prism levels to correct sextant tilt.
    From: Richard B. Emerson
    Date: 1999 Nov 02, 6:41 AM

    [...]
     > This is pretty much what I had in mind and the idea has been exploited.
     > Celestaire used to sell such a prism, which clipped onto the left hand side
     > of the horizon glass. They might still do, I have not looked at their
     > catalog recently. The claim was that verticality to 0.5 degrees was easily
     > achievable using this device, which cost around $40 ten years ago.
    
    Celestaire no longer lists the Davis prisms either in their 2000
    catalog or their web page (www.celestaire.com).  They can be reached
    via e-mail at info{at}celestaire.com.
    
    One of the benefits of a split horizon mirror is the vertical edge of
    the mirror gives a reference line to sequere the sextant with the
    horizon.  From there, a little rocking is all that's needed to be sure
    the sextant is truly vertical.
    
    Rick
    S/V One With The Wind, Baba 35
    

       
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