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    Re: Azimuth computation formula in Pub. 229
    From: David C
    Date: 2021 Jan 16, 19:03 -0800

    A while ago I asked about the calculation of Z. It turned out that there were four basic  formula tyes, depending on the inputs -   d t l,  d h l,  d h t or  h l t. Your formula is of the d t l form. Checking my notes I have  seven references to the d t l formula but only one reference provides a derivation. I have attached a page from Norie which shows the derivation of the A + B = C formula. Maybe from this you can derive your formula?

    Do not worry if you cannot. Decades ago when I was at school I considered myself brilliant at trigonometry. Today I get lost if I attempt even the most basic derivation. I am happy to accept  formulas as given. I mentioned the four types of formula for Z. I checked each one with a pocket calculator to satisfy myself that they were correct.

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