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
Pole).
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 |
Equator |
Celestial Equator |
Ecliptic |
Horizon |
Latitude |
Declination |
Zodiacal Latitude |
Altitude |
Co-Latitude |
Polar Distance |
Polar Elevation |
Zenith Distance |
Parallels of Latitude, or Latitude Circles |
Diurnal Circles |
Latitude Circles |
Altitude Circles |
Meridians |
Hour Circles |
Longitude Circles |
Vertical Circles |
Longitude |
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 .... |
Ascendant |
Descendant |
Horizon |
Medium Coile (MC) |
Imum Coile (IC) |
Meridian |
Equatorial ASC |
Equatorial DSC |
Polar Axis |
Vertex |
Equatorial Ascendant |
Prime Vertical |
Co-Ascendant |
Co-Descendant |
Co-Equator |
Polar Ascendant |
Polar Descendant |
Co-Polar Axis Circle |
The Vernal Equinox |
The Autumnal Equinox |
Equator |
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
astrologers.
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.
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