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    Quadrants, was: Preston's paper on Lewis & Clark's Navigation
    From: Trevor Kenchington
    Date: 2003 Jun 8, 09:11 -0300

    George Huxtable wrote, as part of a much longer contribution:
    > an octant in normal use can measure an angle
    > up to 90? only (compare with 120? for a sextant).
    Is that invariably true? I have seen at least one quadrant/octant with
    dual peep holes. (The particular example that I recall is in the
    Peabody-Essex museum in Salem, Massachusetts.) Using the second eye
    position would still confine the instrument to a 90-degree arc but it
    would not be the arc from 0 to 90, more like 30 to 120.
    I have never read anything about such an instrument, nor how one might
    be used, but it may be unsafe to simply assume that any quadrant was
    incapable of measuring altitudes greater than 90 degrees.
    Trevor Kenchington
    Trevor J. Kenchington PhD                         Gadus@iStar.ca
    Gadus Associates,                                 Office(902) 889-9250
    R.R.#1, Musquodoboit Harbour,                     Fax   (902) 889-9251
    Nova Scotia  B0J 2L0, CANADA                      Home  (902) 889-3555
                         Science Serving the Fisheries

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