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    Re: No Lunars Era
    From: Henry Halboth
    Date: 2004 Dec 7, 10:37 -0500

    Please Frank - you really are a wonderful upstart, I would really hope
    that all of us are well aware that "dead" reckoning is a corruption of
    "deduced" reckoning, at least so the story goes.
    
    On Mon, 6 Dec 2004 19:32:39 EST Frank Reed  writes:
    > Ken M wrote:
    > "I have to do a lot of
    > double checking to eliminate errors but I think  that in the days
    > when log
    > tables were in common use and arithmetic  calculation was heavily
    > drilled
    > at school, a lunar could easily be done in 30  minutes by an
    > experienced
    > navigator."
    >
    > I agree that they could be done with relatively little time. I would
    > say 20
    > minutes with a little experience, but the idea that this was "common
    > math" I
    > don't believe at all. The only thing a navigation instructor could
    > take for
    > granted in his students was knowledge of basic addition and
    > subtraction. But
    > really, that's all you need. Sometimes a blank slate is easier to
    > work  with.
    >
    > And:
    > "Confidence in the result would come from comparing the lunar
    > longitude  with
    > the ded reckoning."
    >
    > Ded instead of dead? That might be another interesting topic for
    > discussion.
    >
    > But to your point, the comparison with the DR longitude was the ONLY
    > way
    > that navigators could get confidence in their results and sometimes
    > too much
    > confidence. It's easy to subconsciously "adjust" lunars, both in the
    > observations and the calculations. How often did navigators work
    > back through  their
    > calculations and find an error when none was present in order to
    > bring  their
    > lunar longitude into line with their DR longitude?
    >
    > Frank R
    > [  ] Mystic, Connecticut
    > [X] Chicago, Illinois
    
    
    

       
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