The geocentric wheel and planets as seen from Earth

This morning (9 Sep 2021) I was experimenting with different ways of viewing our solar system. The following images show the geocentric perspective from Earth as well as that of an observer outside our solar system at the same moment in time (about 6 AM at my location in Connecticut).

Inner figure: heliocentric view with Sun at center (not to scale).
Outer wheel: geocentric horoscope wheel with Earth at center with the heliocentric positions projected from Earth as a central point onto the tropical zodiac.

In the above figure, one can see that as viewed from Earth, the Sun will soon rise in the east, followed by Mars, Mercury, the Earth’s Moon, and Venus, in that order. Here is an enlarged image of the heliocentric view, which is obviously not to scale:

If we were to recast this heliocentric image as a geocentric horoscope wheel, the Earth would be in the center and the planets, Sun and Moon would be projected onto the zodiac signs encircling the figure.

About Anthony Louis

Author of books about astrology and tarot, including TAROT PLAIN AND SIMPLE, HORARY ASTROLOGY, and THE ART OF FORECASTING WITH SOLAR RETURNS.
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2 Responses to The geocentric wheel and planets as seen from Earth

  1. Peter Orne says:

    Hi Tony,
    Ever take requests? I would love to read your review of this Astrology Podcast episode and learn your thoughts about the system (Alcabitius) so definitively favored by Luis Ribeiro.

  2. Hi Peter,
    The podcast in which Luis Ribeiro explains the various house systems is excellent. It is probably the best lecture I have heard on house division. Luis presents the material clearly, and his graphics are great aids to understanding. His point about the need to study the astronomical/mathematical works in addition to astrological texts is well-taken.

    The so-called Alcabitius system of quadrant house division dates back at least to the 5th century CE and is quite elegant and logical. Unlike the so-called Porphyry system, which is based on the arithmetic trisection of the ecliptic markers of the quadrants, without regard for the astronomy, Alcabitius takes into account the amount of time it takes for the degree of the Ascendant to rise to the midheaven and divides the trajectory of the Ascendant degree as it moves from the boundary of one quadrant to the next due to the axial rotation of the Earth. My hunch is that the idea underlying Alcabitius, and its popularity as the standard system in medieval times, arose from the Hellenistic emphasis on the importance of ascensional times of the zodiacal signs (the whole-sign topoi) in the prediction of events. Martin Gansten, who advocates the Alcabitius system, pointed out in his book on primary directions that there was a tendency in the literature to use the same method to do primary directing as to do house division.

    As Luis points out, the Alcabitius system was the standard of house division for several centuries. I seem to recall that Tom Callanan mentioned that even William Lilly used Alcabitius in his early studies of astrology before he switched to Regiomontanus, but I can’t find the reference at this time. Alcabitius cusps are usually quite close to Porphyry cusps but the have the “advantage” of corresponding more closely to astronomical reality, whereas Porphyry is more a theoretically mathematical procedure, somewhat akin to our modern use of midpoints of degrees on the ecliptic.

    Placidus was certainly aware of Alcabitius houses but, after a careful reading of Ptolemy, he realized that Alcabitius did not completely coincide with Ptolemy’s method of primary directing, which was more of a ‘space-time’ concept. As a result, Placidus refined the underlying thinking of the Alcabitius system to produce the so-called “time-line” method of accounting for both the space and time traversed. My hunch is that Placidus was influenced by his study of Kepler’s laws of planetary motion in which planets on their orbits around the Sun sweep out equal areas in equal amounts of time. The more I study Placidus, the more I am impressed by his brilliance.

    To answer your question about my view of Alcabitius, I agree that it was the standard of practice for many centuries and that it continues to be effective in day-to-day astrology. I often cast charts with Alcabitius houses and find that they work just fine, especially with horary charts. If you want to do charts in a genuinely traditional manner, by all means cast them with Alcabitius houses and you will be in the company of some of the greatest astrologers of all time.

    On the other hand, I’m a great fan of Placidus for his brilliance and originality, and my go-to house system is Placidus, also because it works so well with the proportional semi-arc method of primary directing espoused by both Ptolemy and Placidus. One might say that Alcabitius is the Isaac Newton of house divisiion, whereas Placidus is its Einstein. That said, there is no reason to avoid using proportional semi-arc directions with Alcabitius house; Martin Gansten does this and he gets very good results.

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