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    Re: Cryptic Slide Rule Formulae
    From: Bill Noyce
    Date: 2016 Jan 24, 17:07 -0800

    Chiming in late...

    #1 is the biggie: the "law of cosines" formula for altitude

    #2 is a formula for azimuth that can be used once you have the altitude

    #3 and #4 turn these formulas inside-out to make them useful for star-identification:

        given an altitude and azimuth, they return declination and hour angle.

    I was thinking that #5 looks like the simplified formula for finding sunset/sunrise,

       when the center of the body is at 0 degrees altitude ignoring dip and refraction.

       But I think that is just tan d * tan L, so this may be something different.

    #6 and #7 didn't look familiar to me, but I think you already have answers for those.

      -- Bill N

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