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House Division

House Division

Signs and Houses are not the same. Signs are twelve-fold divisions of the zodiac which is a belt of space along the ecliptic extending to 8° on either side. Planets traverse through the signs at different speeds in their own
orbits slightly inclined to the ecliptic.

Houses are divisions of space below and above the horizon of a place. We know that the earth rotates and also revolves round the Sun. Because of the diurnal motion of the earth, the planets appear to rise in the eastern
horizon of the place, reach the mid-heaven and set in the West.

The above picture shows the principle of house division.
The horizontal line (East to West ) is the horizon of the place. The inner circle is the ecliptic. Z is the zenith, the point above head in any particular locality. It is not the Medium Coeli which is South of it ( the M.C. is the
highest point the Sun reaches on any particular day ). The sun and the other planets travel along the ecliptic.

The houses are marked 1,2,3 etc. Houses 1 to 6 are below the horizon (night houses). Houses 7 to 12 are above the horizon ( day houses ). The Ascendant, generally, is the point where the ecliptic cuts the horizon of the place.

As the pole of the earth is inclined at 23 1/2° to the ecliptic and the earth is elliptical in shape, at any given moment, the heavens portray different pictures at different places.

There are various systems of house division, a discussion of which is beyond the scope of this article. However we shall give a brief account of the different house systems. They can be broadly classified into three types,
based on the Ecliptic, Time and Space. To understand the principles behind the various systems of house division, the following points must be borne in mind.



Definition of Terms

Celestial sphere: The sphere formed by the extension of the space surrounding the Earth.

Celestial equator: A great circle parallel to the Earth's equator projected into the celestial sphere along which right ascension is measured.

Co-latitude: The complementary angle of the terrestrial latitude. The city of Bangalore is located at 13° North terrestrial latitude; the co-latitude of Bangalore is 77° (the angular distance of the place from the earth's North

Co-equator: The mirror image of the earth's equator (the equator which is mathematically associated with the co-latitude of a locality on the earth).

Co-polar axis circle: The great circle formed when the mathematics used to derive the polar axis circle is mirrored from the Earth's poles, rather than from the Earth's equator.

Ecliptic: That great circle of the celestial sphere which the Sun traces, when seen from the Earth, in its annual motion.

Euatorial system: A sphere of space using the celestial equator as its main central circle or equator.

Great circle: A circle contained within the celestial sphere which has as its center the center point of the celestial sphere.

Hour circle: A great circle which is perpendicular to the Celestial Equator and which passes through a particular body in space.

Celestial horizon: A great circle of the celestial sphere formed by the projection of the horizon of a locality on the earth.

House circle: A great circle which has as its poles the North and South points of Horizon and which is perpendicular to the Prime Vertical.

Local sidereal time: The time calculated for a horoscope when a time of event is added to the longitude correction, the time zone correction, the acceleration, the delta T correction, and ephemeris.

Meridian: A great circle of the Horizon system which passes through the Zenith, the nadir, and the North and South points of the horizon.

Zenith: The North Pole of the horizon system. The point of the horizon system which is over your head.

Nadir: The South Pole of the Celestial Horizon, Opposite to the Zenith.

Obliquity: The angle in space formed between the ecliptic and the celestial equator. At present it is 23°-27" and is decreasing slowly with time.

Polar axis circle: A great circle which passes through the North and South Poles of the Earth and the East and West points of the Horizon.

Vertical circle: A great circle perpendicular to the Horizon, passing through the Zenith and the Nadir.

Prime verticalL: A great circle which passes through the Zenith, the Nadir and the East and West points of the Horizon of the place perpendicular to the Meridian.

Zodiac: A broad band of space of the celestial sphere extending to 8° on either side of the ecliptic. This is like a window. The constellations lying several light years away visible through this window are taken for astrological
considerations. The Zodiac is divided into 12 solar mansions starting from Aries and 27 lunar mansions with the asterism Ashwini as the beginning.


Earth System

Equatorial Sys.

Ecliptic System

Horizon System

North & South Poles

Celestial Poles

Ecliptic Poles

Zenith; Nadir


Celestial Equator





Zodiacal Latitude



Polar Distance

Polar Elevation

Zenith Distance

Parallels of Latitude, or Latitude Circles

Diurnal Circles

Latitude Circles

Altitude Circles


Hour Circles

Longitude Circles

Vertical Circles


Right Ascension

Zodiacal Longitude

Azimuth Angle

Greenwich Meridian

Hour Circle of Aries

Local Meridian

Prime Vertical


Sensitive Points

  Its opposite

Intersection of the ecliptic and the ....




Medium Coile (MC)

 Imum Coile (IC)


Equatorial ASC

Equatorial DSC

Polar Axis


Equatorial Ascendant

Prime Vertical




Polar Ascendant

Polar Descendant

Co-Polar Axis Circle

The Vernal Equinox

 The Autumnal Equinox


Moon's North Node

South Node

 Plane of the Moon's Orbit


I. Ecliptic based house systems

Equal houses
a) The intersection of the horizon and the ecliptic is taken as the ascendant. The other houses are 30° in length, starting from the ascendant along the ecliptic. Note that the cusp of the X house is not the Meridian Coile.

b) The MC is taken as the reference point and the other houses are equal in measure along the ecliptic. Note that the ascendant is not the intersection of the horizon and the ecliptic.

c) The Whole Sign system: The sign which contains the ascendant is taken as a whole and this is the first house. The starting point of the house is 0° of the sign. The Whole Sign system is the one followed by most traditional

II. Quadrant systems
The arc of the ascendant and MC (cusp of the X) is taken as the basis and other cusps are determined. For example Porphyry trisects this arc to get the cusps of house XII and XI. Cusps of houses II and III are got by
trisecting the arc of the ascendant and the IC. Cusps of other houses lie opposite to these houses.

(a) Time based house systems

The Koch house system, also known as the Birthplace system, is a time-based system introduced by Walter Koch. For cusps above the horizon: the semi-diurnal arc is trisected; then, altitude circles (small circles parallel to
the horizon) are drawn through the points of trisection; 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. The MC and
ascendant are the same respectively, as in the quadrant systems. This system fails in high latitudes.

The Placidian, Topocentric, Regiomontanus are examples of some more Time based house systems.

(b) Space based house systems

Meridian House System
The Meridian house system was proposed by the Australian astrologer Zariel (David Cope). This system is also called the Equatorial House System.

Equal mid-heaven houses on the equator are projected by meridian circles of right ascension to the ecliptic. Each house is exactly two sidereal hours long. The MC is the cusp of the tenth house and the Equatorial Ascendant is the cusp of the first house.

Each house system has its own merits and demerits. Some systems do not work on high latitudes; some others are based on complex and fascinating mathematical factors but not much of astrological relevance.

It is one's experience and purpose which could decide on which system is the best.