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Dear David,

Thank you so much. Having included on one same post all your results will enable interested readers to have everything at hand, avoiding retrieving pieces and bits everywhere. So, thanks again.

For future comparison to interested readers, I have simply added own values (AMC's) including comments when deemed necessary.

Thanks again, David

Antoine

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Spherical Trig

Initial Course to London from New York:  051° 13’ 07.32”     AMC 51°13' 07.42"
Initial Course to New York from London:  228° 21’ 10.8” (Typo ? 288° vs. 228°)   AMC 288°21'10.78"    
Great Circle Arc: 5,577.886km       (Typo ? 5,567.886 vs. 5,577.886)

AMC 5,567.890 km (0.874 532 102 Rad)

Longitude for course = 270/090: 023° 03.3’W

Ellipsoidal Trig

Geodesic London to New York: 5,586.662km assuming you stand on the same spot on deck when you arrive that you were standing on when you set off.   AMC (Vincenty's Method) 5,586.660 km and

AMC (Euler)

Departure Radius 6,389.591656 km, Arrival Radius 6,377.565812 km  Mean Radius 6,383.573 071 km

Mean Radius * Great Circle in Radian : 6,383.573 071 km * 0.874 532 102 = 5,582.639 576 km

Initial Course to London from New York:  051° 14’ 50.3” (rather from NY to L ?)
Initial Course to New York from London:  228° 23’ 32”  (rather from L to NY ? + typo ?  288° vs. 228°)

AMC (Vincenty's Method)  NY to L 051°14'50.3" and L to NY 288°23'32.1"

AMC (3D Geometrical Method) NY to L  051°15'26.5"  and L to NY 288°23'29.8"

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Quoting values to one metre and 1/100^th second of arc are of course purely academic

Yes, of course :-)