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    Re: Accurate quartz watches
    From: Peter Fogg
    Date: 2005 Mar 19, 20:18 +1100

    Keeping a log just records the raw data; it makes sense when plotted as a
    graph. I use the elapsed time (days, weeks, etc) on the horizontal axis, the
    seconds above/below zero (perfect time) on the vertical axis.
    
    If the rate is stable the graphed line rises/falls as a straight line. If
    the line bends or, worse, turns to the other direction, the rate is
    unstable. When the watch is reset the line begins again, ideally parallel to
    the old one.
    
    With 3 graphs (or more) to compare, the time can usually be calculated and
    accuracy checked to the nearest second, well into the future - as would be
    needed without external verification of correct time.
    
    The beauty of this simple system is that there is no need for rare,
    expensive and vulnerable timepieces. Almost any clock/watch can potentially
    be used, such as the pool of crew's watches; as a back up when other sources
    of correct time are unavailable.
    
    The authority, to return to my earlier posting, is not any of the watches,
    but the log (graph).
    
    
    

       
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