Opposition
The opposition is, in astrology, an aspect formed between two planets separated by 180 degrees on the zodiac. It belongs to the five major aspects and signals a polarity, a tension between two complementary poles.
Origin and etymology
The opposition was codified by Claudius Ptolemy in the Tetrabiblos in the 2nd century, among the fundamental aspects derived from the harmonic division of the circle. The Latin word oppositio translates the Greek diametra, which designates the diameter of the zodiac. The medieval Arab and then Latin tradition, notably in Guido Bonatti in the 13th century, traditionally classifies the opposition among the malefic aspects, alongside the square. Johannes Kepler in Harmonices Mundi (1619) confirmed the opposition among the main aspects, and correlated it with the full moon, which is its most visible illustration: the Moon in opposition to the Sun.
Evolution and tradition
The traditional reading saw the opposition as an open conflict. 20th-century astrological psychology deeply modified this interpretation. Dane Rudhyar, in The Astrology of Personality (1936), presents the opposition as a polarity of consciousness, where two functions must learn to recognize each other. Stephen Arroyo and Liz Greene extended this re-reading: the opposition signals less a fight than a dialogue to be established between two poles. The orb of an opposition varies by school, generally from 6 to 10 degrees, with a wider tolerance for the luminaries.
Practical use
A natal opposition between two planets signals a structural dilemma: for example, a Sun-Moon opposition often indicates a duality between daytime consciousness and inner life. Oppositions always involve two complementary signs (Aries-Libra, Taurus-Scorpio, etc.) and two opposite houses in the chart. Transits forming oppositions to a natal planet mark moments of awareness, sometimes conflictual. On Tarotoui, oppositions are automatically identified in chart calculations. Many modern astrologers consider the opposition a driver of maturation, provided both poles are integrated.
Going further
The opposition is not synonymous with insurmountable conflict. Its resolution requires integrating both energies, not eliminating one of them. Note that the monthly full moon is a Sun-Moon opposition, which makes it the most regularly observed aspect. The nodal axis is also a structural opposition between North Node and South Node.