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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Spherical triangles versus plane triangles
From: David Pike
Date: 2025 Sep 17, 01:20 -0700
From: David Pike
Date: 2025 Sep 17, 01:20 -0700
After sleeping on it, the general case appears not to be that difficult. It's two sides and an included angle. You could make a spreadsheet.
Diff=root( (n4)squared + (n3)squared) – arc cos ( (cos(n4).cos(n3)) + (sin(n4).sin(n3).cos90))
but (sin(n4).sin(n3).cos90 is always = 0, so you can forget that bit. Tested for 3&4 degrees. Got to go; Zephyr awaits. More tonight. DaveP
