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    Ex-meridian sights -
    From: Russell Sher
    Date: 2001 Feb 13, 11:07 PM

    Barrie - Your suggestion is in fact something that I have seen in a
    navigation examples book of mine. It is possible if the body is close to the
    observer's zenith around LAN to plot the circle of position (COP) from the
    altitude (since HO will be large and the COP radius small). Of course the
    altitude may be a bit too close to 90 degrees for a desirable observation.
    Then a LOP is taken just after (or could have been just before) this and the
    COP intersected with the LOP - assuming that the distance run between the
    two was insignificant. Perhaps someone has tried this.
    barry wrote...
    Most interesting. The Ex meridian method stems
    from ancient times before the good Marc. Ste. Hilaire position line method.
    However it appears
    to be time honoured especially with DOT examiners. What has always
    interested me is
    why not simply use a sight taken 10 or so minutes
    before or after noon ( up to 30 or so minutes
    allowed by ex-merid tables) as a simple P/L. It
    can be used with future or past P/L's to give a
    position. (snip...)

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