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    Re: Data from three lunars, with some comments
    From: Dan Allen
    Date: 2003 Jan 14, 14:07 -0800

    On Tuesday, January 14, 2003, at 11:55 AM, Fred Hebard wrote:
    > I checked the 12/27/02 data (and the others) by plotting the observed
    > distance against the time of observation.  I was stunned and
    > delighted by how well the data fit a straight line (and one expects
    > this line to be straight over short intervals), with an R^2 of better
    > than 0.997.  I then picked the best observation, one that was most
    > centered on the regression line, and used that to compute time with
    > Bruce Stark's tables.  This was the 6:31:17 observation.  The time
    > came in at about 12 seconds behind UT1.
    > These data convinced me that my newly purchased Husun sextant was
    > worth repairing rather than reselling (the handle was burst apart by
    > leaking batteries), and encouraged me to explore further.  But I'm
    > not so sure I would have felt that way if the data had been from the
    > 1/8/03 or 1/11/03 sights.
    Thank you for sharing your lunars with us.  I have got to get out and
    start taking lunars myself one of these days.  I am still struggling to
    understand the computations myself.
    Your experience is like my land sights: some are amazingly accurate
    others are not.  We know this because we have the luxury of comparing
    sextant results with an averaged GPS location or a typographic map
    But how would we do without these crutches?  How would we do on a
    ship in a storm?  What statistical measures or rules of thumb can be
    to help throw out the bad sights and keep the good ones?  This is an
    that I am considering more and more.

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