Western astrology

Western astrology is the system of astrology most popular in Western countries. Western astrology is historically based on Ptolemy's Tetrabiblos (2nd century CE), which in turn was a continuation of Hellenistic and ultimately Babylonian traditions.

Western astrology is largely horoscopic, that is, it is a form of divination based on the construction of a horoscope for an exact moment, such as a person's birth as well as location (since time zones may or may not affect a person's birth chart), in which various cosmic bodies are said to have an influence. Astrology in western popular culture is often reduced to sun sign astrology, which considers only the individual's date of birth (i.e. the "position of the Sun" at that date).

Astrology is a pseudoscience and has consistently failed experimental and theoretical verification.^[1]^[2]^[3]

Astrology was widely considered a respectable academic and scientific field before the Enlightenment, but modern research has found no consistent empirical basis to it.^[4]^[3]

Note: these are only approximations and the exact date on which the sign of the sun changes varies from year to year.

Modern modifications to the Ptolemaic system[edit]

Additional planets[edit]

These are the planets discovered in modern times, which have since been assigned meanings by Western astrologers.^[21]

The position of the planets in the of the zodiac,

astrological signs

The position of the planets in the of the horoscope,

houses

The position of the primary angles of the horoscope, namely the line (called the ascendant/descendant axis), and the prime vertical line (called the zenith/midheaven and nadir/imum coeli axis),

horizon

The angles formed by the planets relative to each other and the primary angles, called

aspects

The position of deduced astronomical entities, such as the .

Lunar nodes

- An account of a test of the predictive power of astrology, with references to other experiments.