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    Re: True Distance vs. Observed Distance
    From: Bill B
    Date: 2012 Sep 17, 15:40 -0400

    On 9/17/2012 3:09 PM, Marcel Tschudin wrote:
    > I like your drawing skills, especially the ship ;-)
    Indeed an interesting image. IMHO it would be useful to the novice to
    add arcs from the horizon through the bodies up to the zenith, and a
    straight line perpendicular to the horizon up to the zenith.
    When I first started down the cel nav portion of my bucket list, Frank
    and I had a low-heat-to-light debate regarding refraction to the zenith.
    His contention was, as I recall, that refraction always moved on a
    straight line up to the zenith.
    My position was, sure, but only for one body when facing it. With two
    bodies a "camera view" of their meridians would look like arcs.
    Eventually we reconciled this, confusion probably due to frame of
    reference and semantics. Nonetheless, confusing to a beginner.
    Bill B

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