Aspects and orbs: how astrologers measure angles

Aspects are specific angles between two planets, measured along the ecliptic. The five classical ("Ptolemaic") aspects: conjunction (0°, fusion), sextile (60°, easy cooperation), square (90°, friction), trine (120°, effortless flow), opposition (180°, confrontation and balance).

Planets are almost never at the exact angle, so astrologers allow an orb — a tolerance band. starscore uses 6° for conjunctions, squares, trines and oppositions, and 4° for sextiles, and always publishes the orb so you can see how tight a claim is. An aspect at 0.2° orb is a loud signal; the same aspect at 5° is background hum. Tighter is stronger — when we rank a day's aspects, orb is the sort key.

Applying aspects (still tightening) are conventionally read as stronger than separating ones; the "exact" date is when orb reaches zero, and our predictions are dated to that peak.

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