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    Re: Swinging the Arc
    From: Bill B
    Date: 2012 Aug 17, 17:26 -0400

    Indeed a nice graphic. It did appear the sextant was swung about the
    axis of the scope. I followed a link provided in the site to their
    sextant article
    
    http://en.wikipedia.org/wiki/Sextant
    
    which stated, " 'Swinging' the sextant about the axis of the telescope
    ensures that the reading is being taken with the instrument held
    vertically."
    
    This raises the old topic of whether the sextant should be swung about
    the axis of the scope, or axis of the observer to the body?
    
    If I recall the consensus was axis of observer to body. As I cannot walk
    and chew gum simultaneously, I have never quite figured out how to
    achieve that goal.
    
    I spent considerable time attempting the technique in my last round of
    observations from a pier on Lake Michigan using the Sun, Moon, Mars,
    Saturn and Spica. I did better on my very first beginner's round of
    sights using the home-built cardboard sextant from Celestaire from a 34'
    sailing craft!
    
    My intercepts from the pier ranged from 4!7'away for the Sun to 17'+
    away for the Moon. Standard deviations were into multiple minutes, while
    my SD norm from land is 0!3 or less. On average, observations were an
    order of magnitude worse than my norm, and always away.
    
    So much for theory, at least as I practice it ;-)
    
    If anyone has a "Swinging the Arc for Dummies" article, I would love to
    read it.
    
    Bill B
    
    
    On 8/17/2012 3:45 PM, Hewitt wrote:
    > Here's a nice brief graphic of using the sextant. First one I've run
    > across showing things in motion.
    >
    > Hewitt
    >
    > Sent from my iPad
    >
    > Begin forwarded message:
    >
    >> *From:* Hewitt >
    >> *Date:* August 17, 2012 12:31:23 PM PDT
    >> *To:* "hhew36@gmail.com " > >
    >> *Subject:* *File:Using sextant swing.gif - Wikipedia, the free
    >> encyclopedia*
    >>
    >> http://en.wikipedia.org/wiki/File:Using_sextant_swing.gif
    >>
    >>
    >> Sent from my iPad
    
    
    
    
    

       
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