The angles are defined as the foreground of consciousness, a kind of relativistic notion that everything is relative to the observer, or the experiencer. This is distinct from using the equinoctial measure 'as' the tropical zodiac. Cyril Fagan rediscovered the in ancient Egyptian astrology the historical roots of the constellations. Garth Allen attempted to find in the APEX of the Sun's Way - an astronomical explanation for the division within the physics of the universe itself. Consider that the first step in observational astronomy is to establish the north pole and the resultant north-south Meridian division of the celestial sphere.
Earth is our position of perception to which the heavens are relative.
We are here the perceivers. And that is also a major factor of our relationship to the rest of the heavens. The APEX, which divides the ecliptic plane through the heavens analogously to the way the Earth's tilt and pole divides our day and year, would offer the best explanation I've yet seen of an astronomical basis for the constellations. In this respect it should be noticed that the Sun's ingress into the constellation Capricorn, termed by Garth Allen the Capsolar, and the Moon's ingress therein, the Caplunar, constitute the most important ingresses during the year. Prevented from following in the family tradition through almost totally impaired hearing since childhood, he turned his acutely enquiring mind to other things, many and varied, finally deciding to make the betterment of the subject he loved the most astrology, his life's work.