Astrology is a group of systems, traditions, and beliefs in which knowledge of the relative positions of celestial bodies and related details is held to be useful in understanding, interpreting, and organizing information about personality, human affairs, and other terrestrial matters. A practitioner of astrology is called an astrologer, or, less often, an astrologist.
The core beliefs of astrology were prevalent in most of the ancient world but todays scientific community, at least in the Western World, generally considers astrology to be a pseudoscience or superstition. However, astrology is still heavily practiced and believed in the Eastern World.
A common belief held by astrologers is that the positions of certain celestial bodies either influence or correlate with human affairs. A modern explanation is that the cosmos (and especially the solar system) acts as a single unit, so that any happening in any part of it is reflected in every other part, somewhat representing chaos theory. Skeptics dispute these claims.
Most astrological traditions are based on the relative positions and movements of various real or construed celestial bodies and on the construction of celestial patterns as seen at the time and place of the event being studied. The most common application of this is the birth Horoscope.
The celestial bodies usually considered are the Sun, Moon, planets, stars and the lunar nodes. The frame of reference for such apparent positions is defined by the tropical or sidereal zodiacal signs on one hand, and by the local horizon (ascendant) and midheaven on the other. This latter (local) frame is typically further divided into the twelve astrological houses. These astrological aspects are used to determine the geometric/angular relationship(s) between the various celestial bodies and angles in the horoscope.
The claim of astrology to predict future trends and developments, or predictive astrology, is based on two main methods - astrological transits and astrological progressions. In astrological transits the ongoing movements of the planets are interpreted for their significance as they transit the horoscope. In astrological progressions the horoscope is progressed forward in time according to set methods.
In the past, astrologers often relied on close observation of celestial objects and the charting of their movements. Modern astrologers use data provided by astronomers which are transformed to a set of astrological tables called ephemerides, showing the changing zodiacal positions of the heavenly bodies through time.
Astrocartography, also called Astrogeography is one of several methods of Locational Astrology, which purports to identify varying life conditions through differences in location.