Astrological aspect
An astrological aspect is the geometric angle that two planets form in the natal chart, measured in degrees. Each significant angle describes a specific dynamic between the psychic functions represented by those two planets. Aspects are the living soul of the chart: without them, the planets would be isolated pieces.
Origin and technique
The doctrine of planetary aspects was systematised by Claudius Ptolemy in his Tetrabiblos (2nd century AD), although it was already in use in previous Hellenistic astrology. Ptolemy described five major aspects: conjunction (0°), opposition (180°), trine (120°), square (90°) and sextile (60°). These remain the five fundamental aspects of Western astrology.
In the Renaissance, Johannes Kepler added minor aspects derived from harmonic divisions of the circle: quincunx (150°), semisextile (30°), quintile (72°), biquintile (144°), among others. Each aspect has an orb (margin of angular tolerance): a trine does not need to be exactly 120° to be considered active; it suffices to be within ±6° or ±8° depending on the school.
Harmonic vs. tense aspects
Aspects are traditionally classified into two groups. Harmonic aspects: trine (120°, easy fluidity), sextile (60°, opportunity), conjunction (reinforces if between compatible planets). Tense aspects: square (90°, active conflict), opposition (180°, polarity), conjunction (can also be tense if between incompatible planets).
Tense aspects are not bad: they are the engines of growth. A chart full of trines may be comfortable but flat; a chart with significant squares has challenges but also potential for evolution. An exact aspect (without orb) is stronger; multiple aspects between three or more planets (configurations like the "grand trine", the "T-square", the "Star of David") add extra layers of nuance.
Also known as
- Angular configuration
- Planetary aspect
- Astrological angle