This page was added to this site to illustrate an answer posted on AllExperts.com, and is not meant to be a thorough discussion of the PZS triangle. It will be updated and expanded at some future date, with the discussion below as one example of how to use the triangle.

     Here is the PZS triangle formed by the rising Sun:
     (1) the arc from the Zenith to the Celestial Pole, which is equal to 90 - the latitude
     (2) the arc from the Celestial Pole to the Sun, which is equal to 90 - the Sun's declination
     (3) the arc from the Zenith to the rising Sun, which is 90 degrees.
     In this case, S is the angle made at the Sun by the vertical circle from the Sun to the zenith, and the hour circle from the Sun to the Celestial Pole. If we call that angle S, then the angle the Sun rises at relative to the horizon is also S, as shown in the diagram below. (The Sun's declination circle is also the path it follows while rising, and is at a right angle to the hour circle through the Sun.)