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    Re: Z tangent formula
    From: Peter Fogg
    Date: 2005 Jul 11, 10:30 +1000

    > From: george huxtable
    > But Peter makes it difficult (indeed impossible) for anyone else to
    > reproduce his calculation, by omitting mention of the values of hour-
    > angle,
    > lat, and dec that he has used. If Peter will provide that missing-link, he
    > might get some more informed responses.
    Here we go:
    >The first comes from the problem Mike Burkes
    >posed, that I worked out and posted here on the 2 July.
    >Sun UL Azimuth - in decimal form, and to 3 decimal places if available
    >101            'Bennett book' azimuth tables
    >100.9       Sharp nav. calculator
    >100.982         NavPac, given as 100d 58.9'
    >100.985     Z tan formula
    287d 02'        LHA
    N36d 00'        lat
    S00d 57'        dec
     13d            alt
    I think I've been able to answer my own question. NavPac (and the nav.
    calculator) use internally generated values of declination and Local Hour
    Angle (dec S00d 56.7', LHA 287d 02.1' for NavPac) which could explain the
    small discrepancy. Substituting these values in the Z tan formula gives an
    azimuth of 100.9810198d, or 100d 58' 51.6". The answer quoted above of 100d
    58.9' could simply be the same answer rounded slightly.
    Nevertheless, am interested in finding other formulas for the calculation of
    azimuth for comparison.

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