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    Re: Graphically solving haversine calculation
    From: Jaap vd Heide
    Date: 2015 Nov 12, 06:42 -0800

    Francis,

    I have expanded the azimuth part of the graphical sight reduction I proposed and have taken a look at the LD info you attached.

    I do also think I have to make a remark about precision of the graphical method I propose though. Bacause while acurate, the method I propose lacks the precision I that would think is necessary for it to be of real practical use when it comes to positioning. I haven't done real testing yet, but I wouldn't be surprised to find a spread with a standard deviation of 1°, which means an intercept having a 95% confidence interval of +/- 120 nautical miles.
    (testing on the beach nearby, on the West coast of the Netherlands, could then put me either well into Germany or somewhere on the East coast of the United Kingdom)
    With clearing a Lunar Distance such differences make up an uncertainty of hours.
    For reducing a sight for getting an azimuth, a precision as mentioned would probably be sufficient to check the boat's compas, which is the kind of use I have in mind, besides it just being fun.

    Regards,

    Jaap

       
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