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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Smart and Shearme Position Line Tables
From: Lars Bergman
Date: 2020 May 4, 13:50 -0700
From: Lars Bergman
Date: 2020 May 4, 13:50 -0700
Now a new try on the formula that David C asked about. How to find azimuth when knowing latitude, altitude and hour angle?
cos(azimuth - x) = cot(latitude)·tan(altitude)·cos(x), where tan(x) = csc(latitude)·cot(hour angle)
or, using the more common trig functions
cos(azimuth - x) = tan(altitude)·cos(x) / tan(latitude), where tan(x) = 1 / [sin(latitude)·tan(hour angle)]
That spherical triangle is uniquely defined.
Lars
