Dear Tony, You mentioned that you needed log tan values for "one remaining job," calculating the sun's azimuth. Are you by any chance using the equations from Waugh's book as shown on page 92? If so you are unnecessarily getting involved with logs.
You can do the same calculations using your digital calculator for the trig functions and the multiplications and divisions as in equations: (1) tan M = tan D / cos H (2) tan Z = (cos M) (tan H) / sin ( La -M) (3) tan A = cos Z / tan (La - M) Where M is just an intermediate value, La is the latitude, D is the solar declination (watch out and be sure to use the correct sign, + or - with D.). H is the sun's hour angle. Z is the sun's azimuth that you are seeking. From the 3rd equation you can also get the sun's altitude, A. The first 2 of these equations are the non-log forms of the log equations Waugh gives on page 92 of his book. He gives all three non-log equatios on page 26 of the same book. The only difference is that on page 26 he uses "a" to stand for azimuth, but on page 92 he uses "Z' for azimuth. I have inserted Z in place of a when writing the equations above for the sake of consistency. Enjoy your dialing, Bill Maddux
