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    Re: Dip Short DSLR Camera CN Sun
    From: David C
    Date: 2020 Jul 20, 20:01 -0700

    The  depth of the tunnel (as I called i) is in fact the versine or bend of the curve.

    A formula I have found in a book published in 1958 is

    bend  in inches =   chord in feet squared / 44 / radius in ch

    Now I know why the metric system is superior to the Imperial system that is still used in at least two countries! (I am not sure about Canada - it is probably constrained by its neighbour).

    Here goes......

    chord = 266 nm

              = 1,616000 ft

    radius  = 3444 nm

                317063 chains

    versine = 187191 inches

                 15599 ft

    approximately 4.8 km.

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