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Aspects

Revised 2026-03-12 · Contributors · How entries are written

An aspect is formed when the difference in ecliptic longitude between two bodies approximates a specific angle. The five relationships recognised in classical practice are the conjunction, sextile, square, trine and opposition; these are termed the Ptolemaic or major aspects. A number of further divisions, called minor aspects, were introduced from the seventeenth century onward and are used inconsistently.

Ptolemaic aspects

Conjunction: 0 degrees. Two bodies at or near the same longitude.; Not classified as harmonious or difficult in itself; interpretation depends entirely on which bodies are involved.
Sextile: 60 degrees. One sixth of the circle.; Conventionally read as facilitating rather than compelling.
Square: 90 degrees. One quarter of the circle.; Conventionally read as tension between two functions that must be reconciled.
Trine: 120 degrees. One third of the circle.; Conventionally read as ease, with the frequent caveat in modern texts that ease is not the same as benefit.
Opposition: 180 degrees. Half the circle.; Bodies in opposition are usually in signs of the same modality and opposite element.

Orb

An aspect is rarely exact. The permitted deviation from the exact angle is called the orb, and there is no settled convention governing its size. Traditional practice assigns orbs to the planets rather than to the aspects, so that a conjunction involving the Sun carries a wider orb than one involving Mercury. Much modern practice assigns orbs to the aspects instead, typically eight degrees for a conjunction or opposition and smaller values for the others. The two systems give different answers and neither is standard.

Applying: The faster body is moving toward exactitude with the slower.
Separating: Exactitude has passed. Traditional sources weight applying aspects more heavily.
Partile: Exact to the same degree of longitude.
Platic: Within orb but not partile.

Where two sources disagree about whether an aspect exists in a chart, the disagreement is almost always about orb convention rather than about the positions themselves.

Minor aspects

The semisquare (45 degrees), sesquiquadrate (135), quincunx or inconjunct (150), and semisextile (30) appear in most modern software. The quintile family (72 and 144) derives from Kepler and is used by a minority. Minor aspects are given narrow orbs, commonly two degrees or less, and their use varies enough between practitioners that a chart reading citing them should be read as that practitioner's method rather than as a general convention.

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