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    Re: Measuring Dip in the 18th Century
    From: Alexandre Eremenko
    Date: 2014 Jan 1, 17:11 -0500

    Ken,
    The instrument in the picture is the quadrant of Tycho Brahe.
    Tycho was a contemporary of Wright, and his instruments were
    by far the best in the world at that time.
    Tycho had unlimited resources in comparison with other astronomers,
    he was sponsored by Danish king, his relative, and later by the
    Roman Emperor.
    
    An average astronomer of that time had to make his instruments himself,
    at his own expense. I don't think anything comparable to Tycho's
    mural quadrant existed in England at that time.
    
    Alex.
    
    
    >
    > On 2014-01-01, at 12:03 PM, Brad Morris wrote:
    >
    >> From the pages provided Wright asserts
    >> 1) that the solstice altitudes of the sun were observed with a quadrant.
    >> 2) that the observations were recorded to 1/2 arc minute
    >>
    > Here is an example of a "quadrant" from the late 1500s.
    >
    > http://en.wikipedia.org/wiki/Mural_instrument
    >
    > This is much different from the later reflecting quadrant used at sea.
    >
    > Ken Muldrew.
    >
    >
    >
    > : http://fer3.com/arc/m2.aspx?i=126104
    >
    >
    >
    >
    
    

       
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