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    Re: Haversines with Logarithms
    From: Brian Walton
    Date: 2020 Oct 20, 07:45 -0700

    David C,

    Thank you.

    A gale, and Corvid-19 lockdown now make Wales a “lee shore.”

    My normal home is only 11 miles from the Greenwich Meridian. The EOT, almanacs starting at midday, and sextant errors may explain why I often end up in the wrong hemisphere when reworking old-fashioned time shots. I was fretting over the maths of versiines, when maybe logic was at fault.

    Half the boys in the bombed out street where I grew up couldn’t read or write; 3 generations ago, it would have been worse.

    If you stuck to Western Atlantic summer forenoon time shots to cross with a noon lat, the use of log-versines giving hours, as did the watch and almanac, would have made it easier to memorise a routine.

    We have aviators to thank for simplifying it. I don’t like radians, especially when wearing a L/J as I am now.

    Of course, my great-grandfather could just ask a British flagged ship what his long was, and who was at war...

    Brian Walton


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