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    Re: Sight reduction formulae
    From: John Karl
    Date: 2011 Dec 1, 19:31 -0800

    I think you guys are making the sign conventions used in calculator reductions too complicated (and obscure):

    North latitudes and declinations are positive, south ones are negative, always.

    The angle A returned from the cosine equation for the azimuth angle gives the zenith angle from north, Zn, from the rule:
    If LHA greater than 180, Zn = A,
    If LHA less than 180, Zn = 360 -A.

    Simple?

    The worksheets in my book also show how to simplify things by using the three memories in the cheapest scientific calculators. See the attached copy. It's as easy as 1, 2, 3.

    (Note: the angle A, above, is different than the Z used in tables.)

    JK
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