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    Simple celestial navigation in 1897
    From: Frank Reed CT
    Date: 2006 Feb 25, 21:36 EST

    The online digital collection of the G.W.  Blunt-White Library at Mystic
    Seaport has been expanded quite a bit recently.  There's a "navigation workbook"
    from a Pacific whaling voyage of the Charles W.  Morgan in 1896-97. Note that
    Joshua Slocum, also from New Bedford, was sailing  the Pacific in his little
    sloop Spray at this time, too (the Morgan was in the  North Pacific, eventually
    hunting whales off Hokkaido so they were never all  that close to each other).
    The navigational technique displayed in this  workbook is very simple. The
    latitude is calculated by subtracting the Sun's  observed noon altitude from 89d
    48' and then adding or subtracting the Sun's  declination (the 90 degrees
    minus 12' value is an old approximate combined  correction for dip, refraction,
    and semi-diameter). For the time sights, this  navigator uses the same 12'
    combined correction. And that's it -- day after day,  latitude by noon Sun and
    longitude by time sight.
    The CWM was already 56  years old on this voyage, and whaling was a minor
    business in the 1890s, so  maybe it's not surprising that there's no "rocket
    science" in this navigation.  Nonetheless, this very simple celestial was good
    enough to cross the Pacific  from California to Micronesia and then on to Japan.
    Here's the index to  the digital  collection:
    42.0N  87.7W, or 41.4N 72.1W.

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