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    Re: Jack Aubrey's fixing of longitude
    From: Albert Rodok
    Date: 2011 Jun 20, 15:54 -0700

    Well, I still remember the explanation Jack gave me about the procedure for the intended observation...

    The idea was to determine the exact local time for the moon set. Previously - and using the data contained in the Nautical Almanac - he had calculated the local time of this event for the estimated island position.

    The difference between the estimated and the actual moon-set local time was then used to lay down the island. The exact local time of this observation was determined with the aid of the chronometers (good enough for the short time period since noon).

    "Two seven four" was the azimuth of the moon when her lower lobe touched the horizon. This fits very well with the described situation (Venus above the moon).

    Albert
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