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    Re: The Great Circle Challenge
    From: Bob Crawley
    Date: 2014 Dec 29, 11:31 -0800

    I thought of using the Marine 229 tables. Substitued Difference in Longitude for LHA then Destination Lat for DEC. Unless you can use points with integer Lat,Lon then one either has to interpolate or just use 229 as a rough guide. It took me quite a while to remember how to use the tables and get the sustitutions right but the method could be quite quick and should be useful as a double check. With a bit of interolating between 41d and 42d for Departure Lat I came up with 67d52m (4072nm) and initial course of 26d. On the way I discovered using http://williams.best.vwh.net/gccalc.htm that there is a difference between the calculated spherical trig answer of, I think, 4041nm and the WGS answer of 4023nm.

    Anyway that was a good question and I learned a lot from it.



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