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    Re: No Two-Body Fix Problems
    From: Peter Hakel
    Date: 2009 Nov 6, 13:08 -0800

    From: George Huxtable <george@hux.me.uk>
    To: navlist@fer3.com
    Sent: Fri, November 6, 2009 12:29:42 PM
    Subject: [NavList 10476] Re: No Two-Body Fix Problems

    [parts deleted by PH]

    He and I seem to be agreeing about the existence
    of the same problem, here, though we may be proposing to resolve it in
    different ways. In what way was it explicitly addressed? Was that by the
    cross-check against zenith distance of star2?


    That is correct.


    This leaves aside another matter; whether the cosine formula is indeed the
    best way to determine LHA, when the LHA is a small angle? Wouldn't the sine
    formula be more appropriate, then? That would spoil John's claim that he
    only ever used the one basic formula, however.


    This brings up the haversine function: hav(x) = sin^2(x) = (1 - cos(x) ) / 2.
    I tried it and it does help with the ACOS() problem, thanks for the suggestion.

    Peter Hakel

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