The core beliefs of astrology were prevalent in parts of the ancient world and are epitomized in the Hermetic maxim, “as above, so below”. Tycho Brahe used a similar phrase to summarize his studies in astrology: suspiciendo despicio, “by looking up I see downward”.

Most astrological traditions are based on the relative positions and movements of various real or construed celestial bodies and on the construction of implied or calculated celestial patterns as seen at the time and place of the event being studied. These are chiefly the astrologicalplanets, dwarf planets, the asteroids, the stars, the lunar nodes, Arabic parts and hypothetical planets. The frame of reference for such apparent positions is defined by the tropical or sidereal zodiac of twelve signs on one hand, and by the local horizon (ascendant-descendant axis) and midheaven-imum coeli axis on the other. This latter (local) frame is typically further divided into the twelve astrological houses. Furthermore, the astrological spects are used to determine the geometric/angular relationship(s) between the various celestial bodies and angles in the horoscope.