There are twelve celestial houses in Astrology and a house is constituted with 30 degrees. They are derived from an equal division of the circle of observation in to 12 parts. One-twelfth part of the circle of observation constitutes an astrological house. In astronomy it is the vertical of the latitude belonging to the place of the birth. The stars on the earth show the place of birth.
The rising house is called ascendant and the others are known as angular, succedent and cadent houses. The angles are four cardipoints in the horoscope. The planets in the horoscopic chart are subservient to lagna, and their original nature undergoes modifications depending upon the lagna.
1. The kendras(or Quadrants) : Houses 1,4, 7 and 10. These are highly significant houses.
2. The panapharas(or Successant Houses) : Houses 2,5, 8 and 11.
3. The Apoklimas(or Cadent Houses) : Houses 3,6,9 and 12.
4. The Trikons(or Trines) : Houses 1,5 and 9. These are highly auspicious and, along with the kendras, determine the health, wealth, status, dignity, rise and virtue or a native. The lagna being both a kendra and a trikona, is the most significant of all the houses.
5. The Upachayas : Houses 3,6, 10 and 11. These houses indicate struggle, competition and material achievement.
6. The Trika Houses : houses 6,8 and 12. These are considered bad houses(Duhsthanas). They indicate debt, disease, loss and misery.
7. The Ayu-sthanas(or houses of longevity) : Houses 8 and 3(8th from the 8th). They indicate the length of life and therefore, also the death.
8. The maraka-sthanas(or killer houses): houses 2 and 7.
9. The two halves of a horoscope.
a. Houses 1 to 7 indicate the invisible half and houses 7 to 1 indicate the visible half of the horoscope.
b. Houses 10 to 4 indicate the eastern half and houses 4 to 10 indicate the western half of the horoscope.
It was observed by the ancient Astronomers that many changes occurred within the 30 degree zones mapped out by the Zodiac. It was therefore, found necessary to subdivide each of the twelve sections or Signs of the Zodiac. Using the belt of Fixed Stars which encircle the Earth at the Equator as markers, they divided the Zodiacal Background into 27 sections, the boundary of each being marked by a particular Fixed Star, located close to the Zodiacal belt. These sections are known as the Asterisms or Nakshatras.They begin at the same point in the Constellation Aries which marks the beginning of the Zodiac,. and since each extends over an arc of 13 deg-20', there are therefore twenty-seven of them in the complete circle of 360 degrees.
The Zodiac and the Asterisms form the fixed background to which all the variables or moving points used in Astrology are referred. A sort of backdrop, in front of which the drama of our solar system is played.