(15C) Haversine Navigation

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An extract from Haversine Navigation 8 pgs.

"Abstract
This is to provide a practical means for cruise planning using … the hand held calculator …
…
Background
…
The spherical trigonometry equations taught left an ambiguity when the initial course was close to due east or west. Further solutions using the Spherical Law of Cosines fall apart when the distances are very small; short distances are most important to the vast majority of weekend sailors. Haversines resolved these issues. Today there are dozens of websites that will give you the course and distance between two points on the earth given the Latitude and Longitude of each. Many of these sites report the distance in kilometers which require a definition of the radius of the earth. The haversine method herein described uses a unit radius; thus, a distance as an angle readily resolves to nautical miles; therefore, I am going to limit this to a simple definition of the haversine and practical topics for cruise planning … on the handheld
calculator …
…
2. Calculator
The equations shown earlier are easily implemented into any handheld calculator with memory storage. I have chosen to show an application using the HP 15C calculator that uses RPN … You only have to program your device once. The RPN programming steps are shown …"

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