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    Sextant accuracy
    From: Alexandre Eremenko
    Date: 2005 Feb 13, 17:54 -0500

    On the recent topic of measuring star-to-star distances:
    The Russian book
    "Precision of astronomical determinations of ships position",
    says that
    precision of star-to-star distances strongly
    depends on the position
    of your sextant.
    (I discovered this myself, experimentally, and was
    complaining on the "inconvenient" position on this list
    last October:-)
    If the upper
    star is
    on the right of the
    lower star, the position is "good". In the opposite case it is
    "bad". They say that the results of "special investigations"
    show that the standard error in good position is
    0.15' to 0.18' while in a bad position is is 0.3' to 0.4'.
    BTW, they recommend at least 7 measurements of a distance
    with star-to-star observations.
    Hadley was obviously left-handed. Left handed people make a minority
    (though I am not sure about England:-)
    It is amazing that they imposed the sextant design convenient
    for them on ALL people:-)
    (I read of the unique right-handed sextant in the Bauer book,
    but I've never heard of a sextant with TWO handles, which would
    be the most natural choice. Many reflecting circles have two
    handles, on both sides).

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