The Horizon System (additional notes)
We will return to some additional ideas as to the relationship between the equator and the ecliptic after we introduce the third major astrological system of coordinates, that of the Horizon.
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 through the birthplace or observing point that is parallel to the horizon. The poles of this system are the Zenith (point overhead) and 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 the horizon (for astrological use in this book), starting from the East point and moving in a counterclockwise direction through the North point and on around, in the same way that we are used to measuring houses or signs.
The Horizon system is built around the specific place on Earth of any birth or event and all other objects such as planets, stars, cities, etc. are then expressed in terms of how they were oriented or appear from this perspective. The horizon system is most like the standard road map in that it has a North-South-East-West orientation. The North-South axis is identical to the celestial meridian running from the north celestial (or geographic) pole through the observer to the south celestial pole. The East-West circIe is called the Prime Vertical and runs due East or West from the observer. It does not follow the East-West geographic parallels of latitude we mentioned. The horizon system is independent from the other systems we have discussed and can be superimposed anywhere on the Earth.
© Copyright © 1997 Michael Erlewine