# Frequently asked questions

## Charts > House Systems

- Overview: Available house systems in the Extended Chart Selection

The following house systems can "Extended Chart Selection" be used:

### Placidus

The Pacidus house system divides the phases of planetary and star movement above and below the horizon into equal-sized parts. A planet on the cusp of the twelfth house, for example, has already passed 1/6 of its so-called diurnal arc, a planet on the eleventh house cusp 2/6, a planet on the MC 3/6 or half of its diurnal arc, etc. The houses below the horizon divide the so-called 'nocturnal arc' of the stars and planets.

So, the Placidus system divides celestial movements and is consequently considered a time-oriented system.

For mathematical reasons, Placidus houses cannot be calculated for regions beyond the polar circles.

The Placidus house system is named after the Italian monk and mathematician Placidus de Titis (1603-1668), but was invented by the astronomer and mathematician Giovanni Antonio Magini (1555-1617).

More information can be found in the Astro Wiki

### Koch

The Koch house system (also called "house system of the birth place") is defined by horizon lines at different times on the day of birth. We calculate the timespan that the MC zodiac degree has spent above the horizon since its rising. The cusp of the twelfth house is where the Ascendant was when 1/3 of this time had passed, the eleventh house cusp is where the Ascendant was when 2/3 of that time had passed. The cusps of houses 9 and 8 can be explained as Descendants for 1/3 and 2/3 respectively of this time span after birth.

Therefore, the Koch house system assigns special significance to the MC-IC axis, because the measure of the division is predefined by the diurnal arc of the zodiacal degree of the MC at birth. Like Placidus, the Koch system divides celestial movements and is therefore considered a time oriented system.

For mathematical reasons, Koch houses cannot be calculated for regions beyond the polar circles.

The house system is named after the German astrologer Walter Koch (1895-1970) but was actually invented by Fiedrich Zanzinger (1913-1967) and Heinz Specht (1925-).

More information can be found in the Astro Wiki

### Campanus

The Campanus house system divides the celestial space above and below the horizon like an orange into twelve equal segments. The 'axis' of the 'orange' lies on the horizon and is aligned from north to south. So, the division into twelve segments happens on the 'prime vertical', i.e. the great circle that runs through the East point, the zenith, the West point and the nadir. The places where the segments or 'slices' of the 'orange' intersect the zodiac, make up the Campanus house cusps.

The Campanus system divides

*space*and is therefore considered a space-oriented house system.The house system is named after the Italian mathematician Campanus of Novara (1220-1296).

More information can be found in the Astro Wiki

### Regiomontanus

The Regiomontanus house system divides the celestial equator into twelve equal segments. Then, great circles are drawn from the North point through these segment points to the South point. The intersection of these lines with the ecliptic (zodiac) make up the house cusps according to Regiomontanus. So, the sky is - similar to the Campanus system - divided like an orange, but the different segments of the 'orange' have different sizes.

The Regiomontanus system is considered a house system defined by space.

The house system is named after the German mathematician, astronomer and astrologer Regiomontanus (Johannes Müller of Königsberg, 1436-1476), but was invented by the Spanish Jewish astrologer Abrahma ibn Esra (-1167).

More information can be found in the Astro Wiki

view list### Equal

The equal house system defines the Ascendant as the cusp of the first house. Each house has the same size ("equal") of exactly 30°. The 10th house cusp therefore does not coincide with the MC but is square to the Ascendant and consequently the highest point of the zodiac above the horizon.

The equal house system has been in use since the time of antiquity.

More information can be found in the Astro Wiki

### Equal (MC)

This house system places the MC exactly on the cusp of the 10th house. Each house has the same size ("equal") of exactly 30°. The Ascendant does not usually coincide with the cusp of the 1st house.

More information can be found in the Astro Wiki

### Vehlow

The Vehlow house system belongs to the equal ("same size") house systems. Here, the Ascendant is placed exactly in the middle of the first house. Ascendant and MC therefore do not coincide with a house cusp.

The Vehlow house system is named after the German astrologer Johannes Vehlow (1890-1958).

### Whole Sign Houses

The Whole Sign house system considers the whole sign of the zodiac that contains the Ascendant as the first house. The following zodiac sign is the second house and so on. Here, houses are always complete zodiac signs. The Whole Sign houses belong to the group of equal ("same size") houses.

The Whole Sign house system has been in use since antiquity and is currently especially popular in Indian siderean astrology.### Whole sign houses, 1. house = Aries

The first house begins at the cusp of Aries, all houses have the same size ("equal"), and each house covers a whole zodiac sign.

### Meridian houses

Similar to the Campanus system, the Meridian system resembles a well-proportioned 'orange' but with the difference that the axis of this 'orange' is not placed on the horizon but runs through the celestial poles. In fact, the celestial equator is divided into 12 equal-sized segments starting at the Meridian. Then, Meridian circles are drawn through these segment points. The Meridian house cusps are created by the intersections of these circles with the ecliptic.

The MC in the Meridian house system is identical with the 10th house cusp but the Ascendant is not identical with the cusp of the 1st house.

The Meridian system can be interpreted as a time-oriented as well as space-oriented segmentation of the celestial sphere. Each segment of the 'orange' covers exactly 30° and exactly 2 hours in sidereal time.

### Porphyry

The Porphyry house system creates the intermediate houses by dividing each of the four quadrants into three equal-sized segments.

The house system traces back to the ancient philosopher and scholar Porphyry (233-305?).

### Alcabitius

The Alcabitius house system divides the diurnal arc of the Ascendant into six equal-sized segments. Then, Meridian circles are drawn through the resulting segments. The places where the circles intersect the ecliptic mark the cusps of the Alcabitius houses. The other house cusps can be calculated by adding 180° respectively. Alternatively, the nocturnal arc can be divided into six parts and Meridian circles drawn through the resulting segments.

In this method, the Ascendant and MC are identical with the 1st and 10th house cusps.

The Alcabitius house system therfore assigns particular significance to the Ascendant-Descendant axis, because the measure of division is given by the diurnal arc of the zodiacal degree of the Ascendant at birth.

The house system goes back to the Arab astrologer Abd al-Aziz ibn Uthman al-Qabisi (lat. Alcabitius †967).

### Krusinski-Pisa-Goelzer

In this house system, first a vertical great circle is drawn through Ascendant, Zenith, Descendant and Nadir. This is then divided into 12 equal-sized segments, and Meridian circles are drawn through the resulting segment points. The house cusps result from the intersections of the Meridian circles with the ecliptic.

In this method, Ascendant and MC are identical with the 1st and 10th house cusps.

This house system was invented by three astrologers independently of each other: the Pole Bogdan Krusinski (1995), the Czeck Milan Pisa (1994) and the Swiss Georg Goelzer (1993).

More information in the Swiss Ephemeris Documentation

### Horizon houses

The horizon house system divides the sky according to the four cardinal directions. The cusp of the 1st house is exactly due East, the 10th is exactly due South. The celestial sphere is divided into 12 segments, like an orange (similar to the Campanus and Meridian system), with the axis of the orange running through the Zenith and Nadir, and its 'equator' resting on the horizon. The house cusps result from the intersections of the twelve segments with the ecliptic.

In the horizon house system, the 10th house cusp is identical with the MC, but the 1st house cusp is not identical with the Ascendant.

### Morinus

In the Morinus system, the celestial equator is divided into twelve equal-sized segments starting from the Meridian. The segment points on the equator are then converted to the ecliptical coordinate system. The ecliptic longitudes of these points make up the twelve house cusps.

In the Morinus house system the 10th house cusp deviates slightly from the MC. Similarly, the 1st house cusp is not identical with the Ascendant.

The house system is named after the French philosopher, mathematician and astrologer Jean-Baptiste Morin (Latin: Morinus, 1583-1656).

An article on Morin's Method of Determination (not his house system!) can be found here

### Polich-Page

The Polich-Page house system (also 'topocentric house system') is mathematically defined as follows: The tangent of the polar elevations of the intermediate houses corresponds to one or two thirds respectively of the tangent of the polar elevation of the Ascendant, i.e. the geographic latitude of the birth place. The individual house cusps are placed on the great circles which intersect the celestial equator at intervals of 30° respectively. In low and middle latitudes, topocentric house cusps tend to differ from Placidus house cusps by less than one degree. Only closer to and beyond the polar circles, the differences become more pronounced.

Beyond the polar circles, the Polich-Page house system sometimes generates absurd and impractical house positions.

The house system was invented by the Hungarian-Argentinian astrologer Wendel Polich (1892-1979) and the English-Argentinian astrologer Anthony Nelson Page (1919-1970) erfunden.

More information in the Astro Wiki

### APC

The diurnal arc and the nocturnal arc of the Ascendant are divided into equal-sized segments respectively. Then great circles are drawn from the North point through the segment points to the South point. The intersections of these circles with the ecliptic mark the APC house cusps.

In the APC house system, the 1st house cusp is identical with the Ascendant and the 10th house is conjunct the MC. However, it needs to be mentioned that the house cusps 12-6, 11-5, 2-8, and 3-9 are not exactly opposite each other.

The house system was introduced by the Dutch astrologer Leo Knegt (1882-1957) and is used by the Dutch

*Werkgemeenschap van Astrologen*(WvA, aka “Ram school”).### Pullen SD (Neo-Porphyry)

The house system Pullen Sinusoidal Delta (also known as Neo-Porphyry house system) determines the house sizes from a sinus function depending on the size of the quadrants. You can find more detailed information on the mathematical process in the Swiss Ephemeris Documentation, chapter 6.1.5.3.

One peculiarity of this house system is the fact that when a quadrant is smaller than 30°, the middle house of the quadrant takes the size 0.

The house system was invented in 1994 by the American astrologer Walter Pullen (born 1971), the author of the astrology software Astrolog.

### Pullen SR

The house system Pullen Sinusoidal Ratio determines the house sizes from a sinus function depending on the size of the quadrants. You can find more detailed information on the mathematical process in the Swiss Ephemeris Documentation, chapter 6.1.5.4.

The house system was invented in 2016 by the American astrologer Walter Pullen (born 1971), the author of the astrology software Astrolog, and should replace the house system Pullen SD.

### Sripati

The Sripati house system first calculates the house cusps according to Porphyry, i.e. each quadrant is divided into three equal-sized houses. Then the cusp of each house is moved to the middle of the previous house.

In this house system, the Ascendant and MC are not identical with the cusps of houses 1 and 10.

The Sripati house system originates in Indian Astrology.

### Carter (poli-equatorial) house system

In this house system the celestial sphere is divided into an 'orange' with 12 commensurate segments. The axis of this orange runs through the celestial poles, whereas its 'equator' comes to lie on the celestial equator (hence the name 'poli-equatorial'). Therefore, the house cusps lie on the Meridians. The Meridian of the 1st house cusp runs through the Ascendant. The Meridians of the other house cusps follow at intervals of 30° each.

In this house system, the 1st house cusps is identical with the Ascendant, but the 10th house cusp is not identical with the MC.

The house system was invented by the English astrologer Charles Carter (1887-1968).

### Sunshine

The Sunshine house system divides both the diurnal and the nocturnal arcs of the Sun into six commensurate segments. Then, great circles are drawn from the North point through the segment points to the South point. The intersections of theses circles with the ecliptic mark the Sunshine house cusps.

In the Sunshine house system, the cusp of the 1st house is identical with the Ascendant, and the 10th house cusp is identical with the MC. However, the house cusps 12-6, 11-5, 2-8, and 3-9 are not in exact opposition.

The house system was invented by the American astrologer Bob Makransky (born 1947).