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    Re: How good were chronometers?
    From: Greg B
    Date: 2006 Mar 9, 15:54 -0500

    Hi Jim,
          You wrote:
    ?Was Summner a bit of an exception in relying on his chronometer and
    subsequently the that first LOP??
    I Reply:
    I have been wondering about that myself. I don?t think it was so much a
    question him being an exception, if previous experience had found that his
    chronometer was trustworthy, why not rely on it? The thing that really
    jumped out at me in the Summner story (that I read) was that he must have
    been pretty desperate to have even considered pre-calculating the points
    which he subsequently discovered made up what we now call a LOP! I know
    there are brighter bulbs then me out there (maybe I got this part all
    wrong) but wasn?t the standard practice of the day to do either:
    1.      Do a simple noon sun shoot for Lat & Lon?
    2.      If you couldn?t do a noon sun shoot for some reason
            say a high cloud deck, then you would try a equal alt.
          ( 2-4 hr before and after) shoot. And interpolate local noon?
    3.      If you were really good at the math, and had favorable conditions; a
    twilight (morning or evening) sight of Polaris and another star, then work
    a full spherical triangle?
    Did I get that right? (If I didn?t please feel free to correct me) If I
    did, then I see no other reason save desperation for  Summner to do what he
    did, (including relying on his chronometer) I think he thought he was
    dangerously close to a lee shore which was also rocky (I know that would do
    it for me).
    mail2web - Check your email from the web at
    http://mail2web.com/ .

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