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    Re: Nautical astronomy was different
    From: Jared Sherman
    Date: 2004 Oct 22, 14:50 -0400

    Bruce-
          "The best method of regulating a chronometer at sea, is by
    ...[observations]...[to] show how much it is too fast or
    slow."
    
     Well, making observations is only the first part of regulating a
    chronometer. To a navigator, the chronometer might be sacrosanct and you
    might only want to note the inaccuracy of the instrument. To an horologist,
    regulating a chronometer means first calculating the error in it, then
    physically adjusting it for less error. Obviously opening it up to adjust it
    exposes the works to more perils (especially on a moving vessel) so
    simply noting the error might be sufficient for navigators. If I know that
    my watch runs 30 seconds per month fast, I don't try to set it any finer, I
    just need to know when it was last hacked. And that's been normaal for a
    long time. Typically in "our" lifetimes, "chronometer" just means a
    clockworks that is accurate within 2 minutes per month. That's all my old
    Accutron was guaranteed to do, although the procedure for regulating it
    (actually, Bulova called it "harmonizing" the tuning coils, not just
    regulating the watch) could bring it in better than one minute per month,
    which was pracitcally unheard of before quartz watches.
    
    I suspect we seek too much of authors when we examine their words too
    closely. If Bowditch said "regulate" meaning only the first half half of
    what others would call regulating the clock...I can live with that. We
    can understand what he means from the context.
    
    Incidentally, the "casual" means of regulating a mechanical wristwatch
    chronometer is to change the axis it is running in. Either to wear it
    inside/outside the wrist, or at night to place it "top" vs "side" vs "face"
    up or down. Due to gravitational pulls on the mechanism, it will run at a
    different rate in each position, and simply changing the position is often
    enough to adjust the rate by a full minute per month. No opening necessary.
    
    Obviously not usual for a boxed chronometer, shock and horror. But it
    would work on them as well.
    
    
    

       
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