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    Computaion of table of offsets.
    From: Gary LaPook
    Date: 2007 Oct 29, 02:01 -0700

    In the discusssion of the St. Hilaire method the subject of the table
    of offsets used to approximate the curved LOP came up. This is table 4
    in Bowditch (1975 ed), table 19 in the online Bowditch and is also
    printed in each volume of H.O. 229. Bowditch gives the formulas for
    this calculation and one of the formulas gives the radius of the
    circle of postion. The formula for this is: R = 3438' cot altitude.
    Ruiz gives a similar formula: R = (60*180/pi) cot altitude which
    reduces to the other formula given in Bowditch.
    My question is why do you use this formula? Why isn't the radius of
    the circle of position simply  60 times the zenith distance? This is
    the formula we have always used for plotting high altitude circles of
    positions around the GP.  Should we use the Bowditch formula for this
    purpose also.
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