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    Re: Sextant accuracies - coastal piloting
    From: Rodney Myrvaagnes
    Date: 2003 Mar 18, 09:07 -0500

    On Mon, 17 Mar 2003 23:05:20 -0500, Arthur Pearson wrote:
    >I take this to mean I can measure the "altitude" of Mt. Desert Island
    >from the summit to the visible horizon while the bulk of the island is
    >still below the horizon and get a distance off.  You don't need to see
    >the bottom of the object to get a distance off by vertical angle.
    >Bowditch provides the formula which I have plugged into my palm pilot
    >for quick use.
    I stand corrected. The geometry is certainly correct. It does have the
    same problems of refraction that celestial sights at low altitudes
    Without trying numbers, My intuition says that the first sight of Isle
    au Haut would give you a horizontal angle of much greater use. The
    charts do have contours that locate the summits pretty well.
    I appreciate Arthur's choice of MDI as example. It is a landfall I have
    made many times, and this gives me another thing to think about and try
    out in September.
    Rodney Myrvaagnes                   NYC   J36 Gjo/a
    "Be careful. The toe you stepped on yesterday may be connected to the ass you 
    have to kiss today." --Former mayor Ciancia

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