posted February 19, 2008 01:49 PM            

Dear Reader,

When I originally wrote A Theory of the Vertex it was in part due to there being little or no astrological information available about the Vertex. My thinking was also influenced by a group of Iranian astrologers in Mashad, Northern Iran who were creating a Farsi astrology program.

Here are two definitions that I found.

Vertex: “The point in space where the Ecliptic meets the Prime Vertical in the west.”

Anti-Vertex: “The point in space where the Ecliptic meets the Prime Vertical in the east (also known as East Point)."

When it appeared that the Vertex only swung on the Western side of an astrological chart I calculated charts for times and locations around the world looking for variances to the Western side only rule. I had expected to perhaps find extreme latitude variations such as is found with Placidus House System charts. The Placidus House System at extreme northern and southern latitudes has a tendency to bunch up Astrological Houses giving charts where one Astrological Sign may dominate three Astrological Houses and where one Astrological House may hold three Astrological Signs.

The Vertex charts I calculated where for the most part at Northern and Southern extremes. Places used were Siberia, Russia and the tip of South America. Many random charts were also calculated but the West side only rule held. I also looked back over charts I had on file and the West side rule held.

I did receive some chart data by email that spoke of a Vertex on the Eastern side of the chart however when I reproduced the data using my astrological software Astrolabe’s Solar Fire the Vertex had moved back to the Western side. My conclusion was a software error or a different calculation method was being used by the chart sent to me. I held with my Western side only rule.

But ... now I have received your chart data that certainly will require the thinking cap to be put back on. December 13, 1979 in Natal, Brazil, 5° S 54', 35° W 12' will produce a chart with the Vertex on the Eastern side of the chart (at least when using Solar Fire software). When this chart is moved forward and backwards through a 24 hour period it seems the Vertex travels through all 12 Houses. Yes that is six Western Astrological Houses and six Eastern Astrological Houses.

My first inclination in finding the reason for the Vertex variance at this location is to say that rather than the Vertex breaking its majority rule of West side only at latitude extremes perhaps its variances are due to Natal, Brazil lying close to the equator.

Now since Brazil is close to the equator it is possible that the Vertex covers all six western Astrological Houses and the astrology software does not differentiate when it has crossed over to the east and should by rights be called the Anti-Vertex.

I have had an answer back from Astrolabe, the makers of Solar Fire software. It does seem that when you are close to the equator that some versions of Solar Fire and possibly other software will confuse the Anti-Vertex with the Vertex. Solar Fire has a software fix at their web site and their latest version will correctly label the Vertex and the Anti-Vertex. This is not a mathematical or calculation error but a labeling issue. So if you are showing the Vertex on the East side of the chart you are looking at the Anti-Vertex and the Vertex will be found in the opposition position on the West side of the chart, in the opposite Astrological Sign and the opposite Astrological House. I would also be interested in what software was used in the calculation of your chart, if you know I can be contacted by CLICKING HERE.

This inquiry has once again opened the door to the Vertex and I shall do some more work in this area and write a 2003 update to A Theory of the Vertex that I will post in this Astrology Forum in the near future.

Again thank you for inquiry and observation.

Tony Waterfall, astrologer

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The vertical great circle results from the connection of East point, Zenith, West point and Nadir. It is not usually represented in the horoscope, but is used to calculate some house systems. Sometimes the East point is shown in the horoscope as "Anti-Vertex" and the West point as "Vertex".