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    Re: Side Error Adjustment in the Horizon Mirror - Soviet CHO-T
    From: Lisa Fiene
    Date: 2004 Oct 14, 09:45 +1000

    As I have interpreted it, the screw on the horizon mirror that is
    closest to the frame is for correcting Index Error, the screw which is
    furthest from the frame is for Side Error (shear).
    
    When I received my sextant from the Ukraine (I'm in Australia), the
    index error was 16' at only 200 metres!  So, it needed quite a bit of
    adjusting, let me tell you.  All's well now though.
    
    Will look at the perpendicularity thread, although I did not find any
    difficulty with the adjustment of the index mirror.
    
    Lisa
    
    
    
    Alexandre Eremenko wrote:
    > I had exactly the same problem.
    > And I tried to fight it in exactly the same way you did.
    > I don't understand why it happens.
    > What do you think the second adjustment screw (on the
    > top of this mirror) is for?
    > For Index correction? Please keep me informed about your findings.
    >
    > (The phenomenon you describe does not occur with the Index mirror
    > and much more rotation of the wrench
    > is required to move it a little bit.
    > Which I think is good).
    >
    > If you follow the perpendicularity discussion,
    > you notice that there is another difficulty with the
    > index mirror adjustment of SNO-T, due to the fact
    > that the rotation axis of the index arm does not pass
    > through the silvered surface.
    > My message of
    > Wed Oct 13 2004 - 17:07:08 EDT which contains a suggestion
    > to SNO-T users in the end.
    >
    > Alex.
    >
    > On Thu, 14 Oct 2004, Lisa Fiene wrote:
    >
    >
    >>With my newly acquired above sextant, doing the above has proved to be
    >>extremely tricky!  No sooner do I make the correct adjustment, I find
    >>that when I lock the horizon mirror with the "L" key, a slight movement
    >>of the mirror occurs, throwing it out of alignment again....  I have to
    >>then go back and fiddle with it more, 'allowing' for this slight
    >>movement that happens when I lock the mirror.  Can take me up to six
    >>adjustments to adjust it.
    >>
    >>Does anyone else have this problem with their SNO-T/SNO-T also?  If so,
    >>are there any 'tricks' to help with it?
    >>
    >>Thanks, Lisa
    >>
    >
    >
    >
    
    
    --
    Kind regards
    Lisa Fiene
    ***************************
    
    CopyCare Pacific Pty Ltd
    Lizard Tunes
    ABN 93 101 046 888
    PO Box 314 Ourimbah NSW 2258
    Australia
    Phone/Fax: (02) 43 627 583
    International: 61-2-43 627 583
    E-mail: lisa{at}copycarepacific.com
    Web: www.copycare.com/content/local/ccpaceng.asp
    
    
    

       
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