Astronomy for Astrologers
West Point -- A point on the horizon to the west of the
observer, where the prime vertical plane intersects the
horizon.
The Horizon System
We will return to some additional ideas about the
relationship between the equator and the ecliptic after
introducing the third major astrological system of
coordinates, that of the Horizon system.
The Horizon system of coordinates represents the third
and last of the spherical systems used in constructing a
natal chart. In this system, the reference plane is one
that goes through the birthplace or observing point,
parallel to the horizon. The poles of this system are the
Zenith (point overhead) and the Nadir (point underfoot).
The latitude-type coordinate in this system is called
Altitude, and is measured from 0° to 90° from the plane
of the horizon to either pole. The longitude coordinate is
called Azimuth, and is measured from 0° to 360° along