Mr. Podmore's article1 will certainly cause several people to write to you, as he is not suggesting the best use of the HP-35. One advantage of the Hewlett-Packard calculators is that one does not need to convert degrees and minutes to degrees and fractions of a degree before beginning the problem. Also one should use the cosine law again to find the azimuth. The usefulness of the calculator is that it can find with ease, both the calculated zenith distance and azimuth (no more tables!).