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    Re: Angles without a protractor
    From: John Huth
    Date: 2012 Oct 13, 09:06 -0400
    This is not quite the same thing, but I made a quadrant by successively bisecting angles using the method one learns in geometry classes.   At a certain point, I used a ruler to bisect the chords and project back onto the arc.   I ended up with 64 increments over 90 degrees.   I then made a kind of 'vernier' by projecting triangles to the midpoint of each angle.   

    When the plumb line hangs down, I not only measure the increment, but also interpolate using the triangle.   I guessed that I had an uncertainty of about 20 arc-minutes.   I actually have to dig in and measure this, and get a genuine distribution of how far off I am.



    On Fri, Oct 12, 2012 at 9:53 PM, Sean C <yhshuh---.com> wrote:

    "...curve giving the correction to be applied to your calculated angle."
    -Robert Bernecky

    I tried drawing two random angles (52° and 80°) using your graph and they were spot on. Thanks, again!

    And Lu, Re your suggestion about 6"...good idea.

    Cheers,
    Sean


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