A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Lars Bergman
Date: 2014 Nov 26, 13:35 -0800
Hanno Ix wrote "here is a simple equation for the azimuth Z".
Simple? Not for longhand calculation according to me, with multiplication, division and squaring.
A more simple formula, similar to the one used for finding altitude, is this:
N = hav(latitude - altitude)
P = hav(latitude + altitude)
Q = N + P
hav(Z) = (hav(polar distance) - N) / (1-Q)
where polar distance = 90° - declination (if lat and dec are of same name; otherwise 90° + declination).
The difficult part is the division with (1-Q), for very small values of Q this could be replaced by a multiplication with (1+Q).
Lars 59N 18E