Compatibility library

Synastry aspects explained

A reference library for Sun signs, planetary placements and synastry. Start with the information you have, understand the method, and keep uncertainty visible.

Check an aspect angle

What is an aspect between two planets?

An aspect describes an angular relationship between two positions in the zodiac. The major angles commonly used in Western astrology are 0°, 60°, 90°, 120° and 180°. The orb is the distance from the exact angle. Calculating an angle is geometry; assigning relationship meaning to it is astrological interpretation.

Read the method first

  • What are the two measured longitudes?
  • Which orb convention are you using?
  • What changes when you consider other chart factors?

Separate the inputs from the interpretation. Identify which chart factors are known, which depend on a birth time, and which conclusions go beyond what the information supports.

Read the distinction carefully

For a concrete check, enter 10° and 130° below: their separation is 120°, an exact trine. Enter 359° and 1° to see the zodiac boundary handled correctly: the smaller separation is 2°, not 358°. The chosen orb controls whether a nearby major angle receives a label.

Check an aspect angle

Already have two planetary longitudes? Compare their angular separation. For example, 10° Aries is 10° longitude; 10° Leo is 130°.

Orb conventions vary between astrologers. Six degrees is this tool’s starting setting, not a universal standard. No account or birth details are required.

Read further