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    Re: Great Circle Initial Course Boston to Wellington?
    From: Sean C
    Date: 2017 Dec 1, 14:57 -0800

    Bruce,

    Assuming a departure from 42°21.9' N, 71°00.3' W and arrival at 41°19.6' S, 174°48.4' E, I get 7,934.8 nm and an initial course of 247.7° using the sight reduction formulas from the Nautical Almanac:

    "Hc" =  asin(sin(Dest. Lat.) ∙ sin(Dep. Lat.) + cos(Dest. Lat.) ∙ cos(dLon.) ∙ cos(Dep. Lat.)) ; Distance = 60 ∙ (90-Hc)

    I.C.A. = 360 - acos((sin(Dest. Lat.) ∙ cos(Dep. Lat.) - cos(Dest. Lat.) ∙ cos(dLon.) ∙ sin(Dep. Lat.)) ÷ cos(Hc))

    Google Earth gives a distance of 7,935.1 nm and an initial course of 247.7°.

    Regards,

    Sean C.

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