On 2011-05-02, W. eWatson wrote:

What formulas would permit Subject? I want a vector in x, y, z. z is
north, and x is south.

This page has part of the math.

http://star-www.st-and.ac.uk/~fv/webnotes/chapter7.htm

Z being north and x being south makes no sense. Maybe you wanted z to be up.

Peter Duffett-Smith's books on astronomical calculations are simpler and
easier to understand than Jean Meeus' books. Try "Astronomy with your
Personal Computer" if you have a little familiarity with BASIC.

Bud