Charting the House Systems

I have read a lot about each house system, some say that they are time-based, others space based and then there is a long explanation about dividing the ecliptic either on the meridian or the equator.  It made me wonder when it comes down to creating the actual chart, does it matter?

     It all started with Porphyry

The Porphyry House system dates from the 3rd Century AD and is named after its creator, Porphyry (233-305 AD)  a neo-Platonist and student of Plotinus.  He devised his system from the writings of Greek astrologer named Orion (150-175 AD) before Ptolemy’s Tetrabiblos was written in 295 AD.  It is the oldest house system and uses Equal Houses like the Ancient Egyptians, but the Midheaven is always the Tenth House Cusp and the remaining houses are determined by trisecting each hemisphere so it can be used with northern latitudes unlike Placidus.   The Ascendant does not form the first house cusp and may not even fall within the first house.


                             Alcabitius liked Ptolemy

Alcabitius is “time-based” system i.e. it is based on the diurnal (sun day) arc of the ascendant.  A Syrian Christian c. 950 AD, he wrote a book on astrology and created his House System to replicate the  Ptolemaic one as stated in the Tetrabiblos; it does not have interceptions but does have unequal houses (i.e. each house cusp has its own start. In the true Equal House system, all houses are exactly the same size & have the same start, see the slideshow for more).  What is nice about Alcabitius is that it causes no distortion at high latitudes so people born in Russia, Scotland etc. can use this method without getting wide distortions — though some actually like that.  See Mary Ann Trump for examples.

Michel de Nostradame (Nostradamus)  used the Alcabitius System for his predictions.


               Alcabitus is out…the Latins move in

The Campanus House System was created by two Mathematician brothers, Johannes and Matthias Campanus, born around 1250 AD.  The Campanus method is “space based” a term that refers to when a House System uses the prime vertical — the great circle that passes through the east and west points of the horizon as well as the zenith (midheaven) and nadir at right angles.  The prime vertical starts at Greenwich England and is what all longitude is based upon.  See this set of Naval cartoons — they are a set of three — for more.

While the Campanus  brothers based their method on the Alcabitius House Method, they made significant changes including being the  first to incorporate the idea of Intercepted Houses.

A problem with Campanus (and its success egiomontanus and Placidius) is that half of the system (zenith to nadir) is equatorial and the other half (east to west) is ecliptic based. They also broke with Alcabitius that that the cusp should mark the center of a house rather than its start.   Campanus,  is still rather popular in Europe today  (thanks to French-American Dane Rudhyar).

                                                 Regiomontanus changes that

Next up was the German Regiomontanus (aka Johann Mueller), a contemporary and supporter of Reverend Martin Luther.  He announced his system as a further improvement on the Campani by changing the cusps from the middle of the house back to the start and also making them fixed — they were immovable because they were space based (like the Campanus ) and not (birth) time or (birth) place based (like Alcabitius), thus it is typically used in horary work

Brother Placidus enters the Fray

Benedictine monk Placidus de Titis (1590-1668) was also a mathematician & he rectified his predecessors mistakes with a “time based” system based on a tri-section of arcs i.e. he literally calculated the time any degree would take to go from the ecliptic to ascend to the Midheaven and then from the ecliptic to the nadir.

Mathematically his method rather complicated, astronomically, according to Mr. Carl Tobey “this was just as bad,”  and despite his effort was similar to his predecessors as it made  unequally divided house systems — each house has a different start point so houses can be very big or small depending upon the location. Despite that Raphael (Robert Cross) based his ephemeris on that one, probably because it was the most modern and not French, and  all the major astrologers followed suit i.e. : Charubel, Alan Leo, Charles E. O. Carter and Marc Edmund Jones because they used his tables.

It is still the most popular one around, though in America the Walter Koch system is a close second.

                                  Placidus is wrong!?

The French Morinus who caught & fixed Placidus’s  errors — he was Kepler’s contemporary — but was vilified in his lifetime for suggesting that the Placidan system was wrong,  and until the 20th Century  Morinus’s  was the most mathematically accurate with houses that are uneven but slightly so.  It can be used at all latitudes.

It is doubtful though that the Britisher’s Raphael and Alan Leo would have used a French system no matter how accurate because of historical prejudices,  and despite Tobey et alia’s objections, I like it and use it.


                            Technology and the 20th Century

Sydney Omarr was good friends with fellow astrologer & astronomomer Carl Payne Tobey, (see here for his picture and wedding announcement).  In Omarr’s  autobiography, My world of Astrology,¹  Tobey discusses the key to their choice of house system:  it is based on the ecliptic North Pole.

The  picture  has 23.5º on the bottom because that is our axial tilt — as the Earth actually tilts to stay on its path around the sun.  That path is called the ecliptic.

So what is the ecliptic North Pole?

It is a mathematical point that is 90º north of the artic circle that is often seen on globes as where all the lattitudes converge.

The distance from the Artic Circle to the regular North Pole is exactly the same as the distance of the Tropic of Cancer from the equator  and the Tropic of Capricorn to the Antartic Circle.

All of this also explains  why on the horoscope bottom is North, top south and the left is East and the right is West.   So why do they feel that’s important?

  1. It divides the horizon into twelve equal sections and has the great circle passing throught he zenith and nadir just like it would in the sky.
  2. The cusp of the first house will not be the ascendant because that comes after the house division and should not influence it.

It does have a relationship to the Campanus system, so a Table of Houses created for that house, can be used by the Zenith or Equal House system but I have seen it called the Whole House System as well.  It was created around the turn of the century by Australian astrologer, Zariel (David Cope).


                                      Going back in time

In the meantime our reference chart of President Bill Clinton is problematic as it does not have interceptions no matter which house system we try and we do want to highlight them.  So, we are  changing our reference point from the Democrat Bill Clinton to the 1940 Republican Nominee Wendell Willkie who ran against Franklin Delano Roosevelt in 1940.


If you are unfamiliar with Mr. Wilkie, read his obituary from the New York Times where they hailed him as “businessman who put politics aside” and ran for office.  Boy had that tune change 75 years later.  NYTimes — Wilkie dies

                                                         Pictures please

Now that with all of that under your belt, click on the Slideshow to see  how the various house systems handle the same horoscope. Look closely as sometimes the differences are not readily apparent, hopefully our review above, helps.





  1. Omarr, Sydney.  My World of Astrology, 1969 edition.  Published by:  WIlshire Book Company, 8721 Sunset Blvd. Hollywood CA 90069.
  2. Another Equal House system was created by  the Dutch esoterist A. E. Thierens.  He also has a rather unusual tarot system that is worth reviewing.
  3. The Meridian System is found in Matrix WinStar, Kepler and Solar Fire.  I have never seen it online.  Like Porphyry, Morinus and Whole Sign  it does not tie the ascendant to the first house.  I have never seen the “Zenith” House system mentioned as such.




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