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    Equal altitudes at noon
    From: Mal Misuraca
    Date: 1997 Feb 14, 10:03 EST

    position seems beside the point.  When the great majority of sailors are
    abandoning celestial for GPS, and thus risking themselves without a
    non-electronic means to navigate, we are unwise to devote so much time to
    whether precise fixes can be obtained with celestial.  That plays the GPS
    game, and GPS accuracy is irrelevant in most cases to sea navigation.
            Landfall is the spot in the ocean where the navigator can switch back to
    coastal navigation.  It may be as much as 30 or more miles off land, depending
    on when the terrain features allow coastal to be substituted for celestial.
    At 30 miles off, some rate of error is obviously permissible, more than enough
    to be covered by the debate we have had here.  (Low-lying terrain calls for
    closer landfalls, and these demand more vigilance and assume a crew well
    attuned to the needs of safety.)
            In this context, the argument over equal altitudes versus lines of position
    seems to me entirely academic.  Sights taken close enough together to yield
    equal altitudes will not satisfy the navigator who tries to use them to
    establish intersecting lines of position; the "cuts" will not be good.  The
    same room for error based on erroneous courses, distances, leeway, and so on
    will infect equal altitudes and running fixes.  The simple fact is, from my
    experience teaching many modern sailors, that many will not take time to
    master the use of sight reduction tables, assumed positions, and local hour
    angles, whereas they will take avidly to equal altitudes and the symmetry of
    the rise and fall of the sun around local apparent noon.  If that gets them
    safely to landfall when their GPS goes south on them, why are we spending so
    much time being shocked, shocked to learn that equal altitudes are being
    resorted to in this establishment?
                                    Mal Misuraca
                                    "Celestial in a Day"
                                    KO6KR, "Passage East"

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