Greetings

Astronomy for Astrologers

The Horizon Sphere

This diagram shows the third (and final) coordinate
system that makes up a birth chart, in this case, the
local horizon measured in Altitude and Azimuth. Here
we are looking at the exact spot on the earth where the
birth took place, using the most local coordinates.
Please note:

1. The Zenith (Z), which is the point directly above the
   birth place, extends out above the birthplace (purple
   dot).


2. The plane of the horizon is 90° from the zenith. This
   is shown by the red semi-arc in the diagram, extending
   from the ascendant (top) to the descendent (bottom).


3. The intersection, of the horizon to the zodiac, at 8° of
   Sagittarius and Gemini, marks the ascendant and
   descendant axis. The ascendant is where the local
   horizon intersects the zodiac.