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    Re: Line of Position Fix
    From: Greg Rudzinski
    Date: 2012 Oct 18, 15:48 -0700

    Lu,

    I will agree with you regarding random errors that the chances are greater being outside the triangle. I will disagree with you regarding systematic errors which are cancelled out when three lines of position are spaced by 120 degrees. The third line of position will also give the navigator a heads up if a blunder has been made by producing a larger than expected triangle.

    Greg Rudzinski

    [NavList] Re: Line of Position Fix
    From: Lu Abel
    Date: 18 Oct 2012 14:37
    I agree that even on land LOPs are likely to be off by a mile or even more and so fixes have that uncertainty; it's just the nature of celestial navigation.

    But I have to question the claim that getting three LOPs will give a better fix. As someone pointed out in a discussion on this list a few years ago, there's only a one in eight chance of a fix even being inside the cocked hat and there's no certitude at all that the fix will be in the center of the hat.


    From: Brad Morris <bradley.r.morris---com>
    To: NavList@fer3.com
    Sent: Thursday, October 18, 2012 12:45 PM
    Subject: [NavList] Re: Line of Position Fix

    Hi Debra
    The best two times of the day are the civil twilights. Those are just before dawn and just after sunset. The best bodies to use are the 57 navigational stars.
    Just as a note, you will want 3 bodies in your fix. It is unlikely that 2 LOPs will cross at your position, in general, and 3 will produced a 'cocked hat'.
    Best Regards
    Brad Morris
    On Oct 18, 2012 3:23 PM, "Debra Hillman" <wombatroo---com> wrote:
    Could somebody help me with my problem . I am learning on my own at present from books on celestial navigation.I need to get a fix with two lines of position but not sure which celestial body other than the sun and the best times of the day to achieve the fix.


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