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    Re: Inverse Grid Magrader Chart
    From: Gary LaPook
    Date: 2010 Apr 22, 12:24 -0700

    Article 309 of Bowditch (1962 & 1977 ed)
    " Transverse Mercator Projection- a special case of the Mercator
    projection in which the cylinder is tangent along a meridian is called a
    transverse (inverse) Mercator ..."
    You won't find this in the current Bowditch. It is also article 209 of
    H.O. 216 (1967).
    Brad Morris wrote:
    > I am reading the "Army Observer's Report of Operation Highjump", Task
    > Force 68 US Navy.
    > Of the navigation reported, the observer reports
    > 1) Beacon Navigation. Homing to the runway by a beacon.
    > 2) Use of the astral or sun compass
    > 3) Magnetic compass
    > a) For the LVT (ground expedition). Observer states not adequate due
    > to swing or oscillation of the compass needle.
    > b) For air navigation, the observer states that the compass, with known
    > variations provided an ability for "a fairly good course"
    > 4) Sun Lines of Position!
    > There is a reference to an "Inverse Grid Magrader" chart and an
    > "inverse grid computer". I would suspect the inverse grid computer to
    > be some type of slide rule. My question is about the Inverse Grid
    > Magrader chart. Has anyone heard of this before? Internet searches
    > yield no help. Could it be that the Army Observer transliterated
    > Mercator to Magrader?
    > A little help would be appreciated!
    > Best Regards
    > Brad
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