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    Re: An All-Haversine Azimuth (from Lat, Dec and dLon alone)?
    From: David C
    Date: 2021 Feb 19, 12:39 -0800

    Frederick wrote

    To obtain azimuth without Hc calculations there are 'good old' methods; such as Lecky's A,B,C tables originally published in 1892

    The A and B tables were first published in the Nautical Magazine in 1846. The reference in front of me says they were published anonymously but I think I have seen  mention of the author's name somewhere but cannot remember. Table C was added by Mr AC Johnson RN (aka Cloudy Weather Johnson). Lecky no doubt published the tables with permission.

    I recommend the ABC tables. Extract two three digit numbers from facing pages; add or subtract the numbers and then find the number in a third table.

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