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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Graphically solving haversine calculation
From: Jaap vd Heide
Date: 2015 Nov 13, 13:25 -0800
From: Jaap vd Heide
Date: 2015 Nov 13, 13:25 -0800
IMHO the poles are interesting all year round.
With P being one of the poles, AP the (assumed) position and GP the geographical position of the sun, when P and AP coincide the navigational triangle is reduced to a line between two points (or better an arc being part of the meridian running through GP) and there no longer is a LHA nor an Azimuth. Whereever you look is to the other pole, so either South or North.
Near the poles, I believe the text is correct, although it will be very hard to either measure or calculate by use of the spherical law of cosines.
I would say this is a quirk in reality, rather than a quirk in the text.