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    Re: Sextant accuracy (was : Plumb-line horizon vs. geocentric horizon)
    From: Bill B
    Date: 2005 Feb 13, 21:22 -0500

    > Jared you wrote:
    > "Centering on the
    > target is something else again, group sizes are measured across the
    > group--not to the center of the target. The group is often not in the center
    > of the target, that's something esle again."
    > Frank replied:
    > So the tightness of the group is one measure of success and closeness to the
    > target center is another? Is that what you're saying? And when you spoke of
    > that half-minute of arc accuracy was that for clustering only or for closeness
    > to the center?
    Would this be the classic example of precision vs. accuracy, touched on in
    an earlier thread? A random pattern of shots placed around the perimeter and
    and center of the bulls eye would be accurate.  A very tight pattern,
    although not near the bulls eyes would be precise (repeatability).  A tight
    pattern in the center of the bulls eye would be both precise and accurate.

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