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    Re: Celestial Navigation In The Gps Age: Typos?
    From: Bill B
    Date: 2017 Sep 1, 00:05 -0400

    On 8/31/2017 3:33 PM, Stan K wrote:
    > As far as the sun altitude corrections go, they consist of refraction ,
    > parallax, and semi-diameter.  refraction and parallax are essentially
    > the same for lower and upper limbs, but semi-diameter goes from limb to
    > center by adding for a lower limb sight, but subtracting for an upper
    > limb sight.  Using some nice round numbers for refraction, parallax, and
    > semi-diameter, in that order:
    >
    Tony
    
    Apologies. In an attempt to be simplistic I made a gross errors. Stan is
    correct, parallax is include in the altitude tables.
    
    I stated, "When we calculate the Hc of a body (especially the sun and
    moon) we are calculating the distance from the horizon to the CENTER of
    the body." It should read. "When we calculate the Hc of a body
    (especially the sun and moon) we are calculating the angle from the the
    CENTER of the body to the center of the earth in the absence of
    atmosphere."
    

       
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