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    Re: Northern Limits of Magnetic Compass Usefulness
    From: Bob Goethe
    Date: 2019 Feb 6, 12:51 -0800

    >>the shadow of the gnomon point will track along one of the date curves on any given date<<

    Well THIS is intriguing, Frank. 

    My mathematical prowess is confined to doing basic sine/cosine/tangent functions with, generally, straight lines...even if the straight lines are across the face of a sphere.

    Am I likely to be able to handle the math to calculate date curves? 

    Or am I better off remembering Clint Eastwood's line from the first "Dirty Harry" movie?  A man's got to know his limitations.

    Bob

       
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