# Astrological House Systems

( Work in progress )

What are House Systems in Astrology?

In most horoscopic traditions of astrology systems, horoscope is divided into 12 segments or houses, whose positions depend on time and location rather than on date. In Hindu astrological tradition these are known as **Bhāvas** (Sanskrit: bhāva; "state", "condition").

Over time, many different methods of house division or house systems also known as domifications, have been suggested. Different house systems are simply a different mathematical calculation formulas, by which we calculate AC, MC and Houses in astrology chart. According to Holden's approach, there are three different types of house systems: **Ecliptic**, **Spatial** and **Temporal**.

Ecliptic Systems

Also known as earliest forms of house division originating in ancient Babylon. These house systems are the ones that are directly based on the ecliptic. These divide the ecliptic itself. This means they link with or run parallel to the signs of the zodiac along the ecliptic. All houses are of equal size of 30°. The 1st house is the whole of the sign that is rising, the 2nd house is the next sign to rise, and so on.

Equal

The equal house system is a method, that divides each of the 12 houses into equal 30° segments starting from the degree of the AC. The cusp or starting point of each house will always be in the same degree of each sign as the AC is in the rising sign. In this system MC floats freely in the top half of the chart, and does not mark the cusp or starting point of the 10th house. Cusp of 10th house is always 90° before the AC. The equal house is one of the oldest systems, which has been in use since the time of antiquity. Evidences show it was already in use back in the 1st and 2nd centuries CE.

Porphyry

In the porphyry, houses are primarly divided along AC/DC axis, which are the cusps of 1st and 7th house, and MC/IC axis, which are the cusps of 4th and 10th house. Then each quadrant of the four quadrants is further divided in three equal-sized segments.

This house system is attributed to Porphyry of Tyros, but it was first described by the 2nd-century astrologer Vettius Valens, in the 3rd book of his astrological compendium known as The Anthology.

Vehlow

This system is similar as the Equal house system, but AC is positioned in the middle of the 1st house. Vehlow method uses the center of the houses and the reason for this is the Thema Mundi as Firmicus described it. The Thema Mundi ("World theme" or "World chart") was a mythical horoscope used in Hellenistic astrology that shows the supposed positions of the seven visible luminaries at the beginning of the universe. It is based on logic behind the sign rulerships, exaltations and meanings of the aspects, among others. It diverges from the theory that the houses and the signs are directly correlated. It is purely symbolic chart.

This house system is named after Johannes Vehlow (21. September 1890, Rügenwalde, Western Pomerania, Germany - 6. March 1958, Berlin, Germany). He was an important German astrologer, known for his main work the eight-volume course in scientific birth astrology called Lehrkursus der Wissenschaftlichen Geburts-Astrologie (Course for scientific natal astrology), in which he tried to establish astrology scientifically. He also created a horoscope for Reich Chancellor Paul von Hindenburg and a horoscope for Reich Chancellor Adolf Hitler.

Whole

In whole sign houses system the 1st house starts at the beginning of the zodiac sign in which the AC is, no matter of exact position of AC. Each house is 30° and covers a complete sign. This system is/was the main system used in Hellenistic tradition of astrology and is still used today in Hindu sidereal astrology. It is thought to be the oldest system of house division. It was developed in the Hellenistic tradition of astrology sometime around the 1st or 2nd century BCE and from there it may have passed to the Indian and early Medieval traditions of astrology. In western world it was completely forgotten, until 1980's and 1990's, when it was reintroduced into western astrology. The difference between equal houses and whole sign houses is in the fact that in whole sign houses the cusp of the 1st house is the beginning of the sign that contains the AC, while in equal houses the degree of the AC is itself the cusp of the 1st house.

Spatial - Space Systems

Also called space-based house systems. The basis of these systems is to take the celestial equator, the horizon or prime vertical and divide it into 12 parts and determine how the resulting house cusps relate to the ecliptic.

Campanus

The Campanus house system divides space instead of time. It takes the meridian as starting point and divide the prime vertical (the great circle that runs through the East point, the zenith, the West point and the nadir) into equal 30-degree sections. These divisions are projected from the pole of the prime vertical onto the ecliptic. Dane Rudhyar (23. March 1895 – 13. September 1985), born Daniel Chennevière, author, modernist composer and humanistic astrologer, recommended the use of Campanus houses in his book "The Astrology of Personality". This is still a popular method used by sports astrologers.

This house system is named after the Italian mathematician, astronomer, astrologer and physician Giovanni Campano or Johannes Campanus (c. 1220, Novara, Italia – 1296, Viterbo, Italia) also referred to as Campanus of Novara. He is known for his work on Euclid's Elements (Elementa, 1255 – 1259). The crater Campanus on the Moon is named after him.

Morinus

In the Morinus system, the celestial equator is divided into twelve equal-sized segments starting from the Meridian. The resulting 12 points on the equator are transformed into ecliptic coordinates. The ecliptic longitudes of these points make up the twelve house cusps. This is a non-quadrant system as the AC is different from the 1st cusp, and the MC is different from the 10th cusp. The house position of a planet depends only on its ecliptic longitude.

This house system is named after Jean-Baptiste Morin (23. February 1583 – 6. November 1656), also known by the Latinized name as Morinus. He was a French mathematician, astrologer and astronomer. He is best known for being an opponent of Galileo. And also for his work on Astrologia Gallica (French Astrology).

Regiomontanus

Instead of the Prime Vertical, the celestial equator is divided into 12 equal parts. Then lines are drawn from the North Pole through these segment points to the South pole of Prime Vertical. The intersection of these lines with the ecliptic (zodiac) make up the house cusps. Because the meridian and the horizon are at right angles to each other and the Poles of the Prime Vertical are on the horizon, AC is a cusp of 1st house and MC is the cusp of 10th house. This is a great advantage over the Meridian and Morinus house system. This system is a mathematically simpler version of the Placidus system, which gives slightly different cusp values from Placidus and does not use varying semi-arc ratios in determining the cusps. There are problems with this system in extreme latitudes, same as with Placidus. Actually Regiomontanus house system was one of the most popular systems in Europe, which was later largely replaced by the Placidus system.

This system is named after Johannes Müller von Königsberg (6. June 1436 – 6. July 1476), better known as Regiomontanus. Regiomontanus wrote under the Latinized name of Ioannes de Monteregio (or Monte Regio, Regio Monte), hence the toponym Regiomontanus. He was a mathematician, astrologer and astronomer of the German Renaissance, active in Vienna, Buda and Nuremberg. The crater Regiomontanus on the Moon is named after him.

Temporal - Time Systems

These divide the daily (24 hour) rotation of the Earth and the resulting house cusps are then related to ecliptic positions.

Alcabitius

This system is based on the equator, to be more precise on the daily cycle. It divides the diurnal arc of the AC into six equal-sized segments and the points, where the lines intersect the ecliptic, mark the cusps of the houses. The nocturnal arc is calculated by adding 180°. In this method, the AC and MC are the cusps of the 1st and 10th house. This system assigns particular significance to the AC/DC axis, because the measure of division is given by the diurnal arc of the zodiacal degree of the AC at birth.

This system is named after Al-Qabisi (Abu al-Saqr Abd al-Aziz ibn Uthman ibn Ali al-Qabisi), latinised as Alchabitius or Alcabitius, Islamic astrologer, astronomer and mathematician, who lived in 10th century AD. He is best known for his treatise on judicial astrology "Introduction to the Art of Judgments of the Stars" (Libellus isagogicus).

Koch

The Koch house system is also called the Birthplace house system. This system is a variant of Alcabitius, some say a more complicated version of the Placidus system, built on equal increments of Right Ascension for each quadrant. To calculate the Alcabitius cusps we use the semiarc of the AC, for Koch we start with the semiarc of the MC. This system divides arcs and projects them onto the ecliptic. For cusps above the horizon, the semidiurnal arc (along a small circle) of the rising degree (AC) is trisected. Then, altitude circles (small circles parallel to the horizon) are constructed through the points of trisection. Finally, the cusps are determined by the intersections of these altitude circles with the ecliptic. For cusps below the horizon, the semi-nocturnal arc is used. AC is a cusp of 1st house and MC is the cusp of 10th house. There are problems with this system in extreme latitudes. Koch houses cannot be calculated for regions beyond the polar circles, for mathematical reasons.

This system was developed by the German astrologer Walter Koch (18. September 1895, Esslingen, Baden-Württemberg, Germany – 25. February 1970, Göppingen, Baden-Württemberg, Germany).

Placidus

Placidus system also known as the Ptolemaic method, is the most commonly used house system in modern Western astrology. It is often described as a time-based system, because it is based on the division of an arc made by a moving point on the ecliptic. AC is a cusp of 1st house and MC is the cusp of 10th house. Placidus houses cannot be calculated for regions beyond the polar circles, for mathematical reasons.

This system is named after the 17th century monk and professor of mathematics, physics and astronomy Placidus de Tito (25. December 1603, Perugia, Umbria, Italy - 1668, Pavia, Lombardy, Italy), who popularized the Placidian system. He did not invent this method. It was developed by the 12th century Hebrew astrologer Abraham Ibn Ezra, one of the most distinguished Jewish biblical commentators and philosophers of the Middle Ages.

Topocentric

Topocentric house system also called Polich-Page, after the creators Wendel Polich and A. Page Nelson, is a recent system, invented in Argentina. It was first introduced in 1961 and later in 1964 for the first time presented to the public in the journal Spica. It's similar to Placidus and it also works for latitudes beyond the polar circles, so some consider it to be an improvement of the Placidus system. The house cusps are always within a degree of those given in the Placidus system. Unlike the Placidus system, the division of diurnal and nocturnal arcs of points of the zodiac, is completely abandoned.