Astrological house

Most horoscopic traditions of astrology systems divide the horoscope into a number (usually twelve) of houses whose positions depend on time and location rather than on date. In Hindu astrological tradition these are known as Bhāvas. The houses of the horoscope represent different fields of experience wherein the energies of the signs and planets operate — described in terms of physical surroundings as well as personal life experiences.

Every house system is dependent on the rotational movement of Earth on its axis, but there is a wide range of approaches to calculating house divisions and different opinions among astrologers over which house system is most accurate. To calculate the houses, it is necessary to know the exact time, date, and location. In natal astrology, some astrologers will use a birth time set for noon or sunrise if the actual time of birth is unknown. An accurate interpretation of such a chart, however, cannot be expected.

The houses are divisions of the ecliptic plane (a great circle containing the Sun's orbit, as seen from the earth), at the time and place of the horoscope in question. They are numbered counter-clockwise from the cusp of the first house. Commonly, houses one through six are below the horizon and houses seven through twelve are above the horizon, but some systems may not respect entirely that division (in particular when the Ascendant does not coincide with the first house's cusp).

The several methods of calculating house divisions stem from disagreement over what they mean mathematically (regarding space and time). All house systems in Western astrology use twelve houses projected on the ecliptic. The differences arise from which fundamental plane is the object of the initial division and whether the divisions represent units of time, or degrees of distance.

If space is the basis for house division, the chosen plane is divided into equal arcs of 30° each. A difference will be made as to whether these divisions are made directly on the ecliptic, or on the celestial equator or some other great circle, before being projected on the ecliptic.

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Wikipedia