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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Using any star for a lunar
From: Alexandre Eremenko
Date: 2005 Apr 5, 21:56 -0500
From: Alexandre Eremenko
Date: 2005 Apr 5, 21:56 -0500
Bill, > In plane geometry the sum of angles of triangle always equal > 180d. Is that always the case in spherical trig? In spherical geometry, the sum of angles of a triangle is NEVER 180. It is always more. The excess over 180 is essentially the area of this triangle. So for small triangles is is close to 180, as it should be, because they are approximately flat, while for big ones it is much bigger. For example, if you mark three arbitrary points on the equator, you obtain a triangle whose three angles are 180 deg each. Alex.
