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    Re: Trans Atlantic
    From: Brad Morris
    Date: 2012 Oct 23, 16:47 -0700

    Hi Kevin

    I have been thinking about your great circle course & the following occurs to me.

    Twilight, for this time of year and at N40 Latitude, is on the order of 30 minutes.  Lets double that to be safe, so 1 hour.

    The deviation between a true, constantly curved great circle course and a straight line approximation will be far less than your measurement uncertainty, especially for a running fix whose total duration is less than one hour.

    In other words, I would not worry about it and just assume a straight line course, instead of a curved course.

    Regards
    Brad

    On Oct 23, 2012 6:57 PM, "Kevin Coulombe" <Kevincoulombe---.com> wrote:

    Greg,
    I was referring to hours run.
    And my shooting technique is probably in need of practice and refinement.
    I think a good round of shots would probably be a lot more useful than a running fix.
    It would be intersting to know what the SEALAND SL-7 navigators did when they were cruising at 30 knots. They had LORAN A and C, OMEGA and DECCA but probably had 1 or 2 days in the Atlantic and 3 or 4 days in the Pacific of pure celestial nav.

    Best Rgds,
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