See also Research for actual charts of people and events
In astrology, a horoscope is a chart or diagram representing the positions of the planets, other celestial bodies, and sensitive angles at the time of any moment in time or any event, such as a person's birth. The term horoscope is derived from Greek words meaning, "a look at the hours." Other commonly used names for the horoscope in English include natal chart, natus, birth chart, astrological chart, celestial map, sky-map, nativity, cosmogram, Vitasphere, soulprint, radix, or simply chart, among others. The process of interpreting a chart is known as delineation.
Choosing a system
Before casting a horoscope, some choices need to be made. First, there is the type of zodiac used, which could be sidereal, tropical in Western astrology and Vedic astrology, or some completely different type of zodiac such as Chinese or Celtic. Second, a house system must be chosen which will determine how to divide the chart into major areas of interpretation. One can also choose different perspectives from which to measure the longitude of planetary positions. Traditionally the chart is cast with earth as the center, and all the planets are viewed from a single point on earth. This is called geocentric astrology, and is the most commonly used method. There is also heliocentric, in which the sun is viewed as the center of the chart. Once all the necessary decisions have been made, a chart can be drawn.
Casting the chart
In most traditions, the chart wheel is drawn with 12 houses, divided according to house system. The first house or Ascendant is defined by the point on the eastern horizon at the exact time and place of birth. This point then determines all the angles of the chart, and the rest of the houses. The signs of the zodiac are then placed over this framework. Planets and other points can be superimposed on top of the houses using an ephemeris to determine the exact position of each point within the zodiac.
Once the wheel is completed, aspects between the chart points can be measured and are sometimes drawn onto the chart as well. The aspects usually considered most important are the conjunction (0Âº), opposition (180Âº), square (90Âº), trine (120Âº) and sextile (60Âº). Other aspects are used as well. The strength of a particular aspect is determined by its orb of influence and the importance of each aspect. Most modern astrologers use an orb of 10Âº or less.
See Casting charts for more details on how to construct a chart.
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