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On Thu, 5 Dec 2002 08:38:08 -0400, Aubrey O'Callaghan wrote:

>
>I have not done the mathematics, but we all know that sometimes when going
>from A to B along a GC track we will head North/South of the rhumb line.
>Perhaps in George's method of 2 composite great circles at point X we could
>still have to head further North to make the second great circle.
>
>In fact the graphics in the Admiralty Manual (fig. 31) illustrates this
>nicely. I don't have a scanner but I'll  see if I can get hold of one if
>the thread continues.
>

The limiting case where the two end points approach the maximum
latitude illustrate the possibility. Clearly both GCs to the mid point
will exceed the safe latitude.

Thinking as I type (dangerous, I know) the borderline case seems to be
when George's two CGs are tangent to the safe parallel at the
mid-course point. But, that would imply that both endpoints lie on the
same GC, so the GC course between them would not go to higher latitudes
anyway.

Warning. My intuition has been wrong before. Even if this sounds good
to you, check yourself. I accepted George's post without question last
night, and only Aubrey made me rethink it.




Rodney Myrvaagnes  NYC                J36 Gjo/a


"Never eat more in a single day than your head weighs." --Jim Harrison

   

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