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    Re: Backlash
    From: Bill B
    Date: 2005 Nov 21, 17:05 -0500

    Alex
    
    > But I do not see any effect of this when I look through the scope.
    > On the other hand, when I measure the index correction
    > with stars of with the Sun, I find substantial backlash:
    > the result depends on whether I rotate clockwise or anti clockwise.
    > Same happens with star distances.
    
    Try this experiment.  Touch the Sun's limbs (clockwise or anti-clockwise).
    Now move the index arm laterally at the arc if you can do that with the
    SNO-T.  Can you see a change in separation or overlap?
    
    > The thing which drives me crazy is that it does not ALWAYS happen.
    > And the amount is different.
    > Sometimes, especially with Sun, I see no backlash.
    > The best results are obtained when I measure the IC say
    > 5 times clockwise and 5 times anticlockwise and then average.
    > And do the same with star distances.
    
    Crazy? Cause and effect? Just why are we trying to do land surveying with
    these instruments and tables? .  For whatever reason, the effect as I
    perceive it is greater in below zero off the arc (Sun's limbs) reading than
    above zero on my Astra.  Spent several (unhurried) hours in the wonderful
    52d F Sun  Sunday exploring that from a folding chair. Why?
    
    Bill
    
    
    

       
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