Synastry: how two charts talk to each other
Synastry lays two people’s birth charts over each other and looks for angles between their planets. It is the oldest way of looking at a couple in Western astrology, and the book starts with it.
What we calculate
For every planet of one person we take every planet of the other and measure the angle between them around the zodiac. If the angle is close to 0, 60, 90, 120 or 180 degrees, it is an aspect. The difference from the exact angle is the orb: the smaller it is, the stronger the aspect feels.
Which aspects matter more
The personal planets say the most about a couple: the Sun, Moon, Mercury, Venus and Mars. An aspect between two slow planets, such as Uranus and Pluto, is the same for most people of the same age, so the free calculation leaves it out.
Your partner’s houses
When the birth time is known, you also see house overlays: which house of your chart your partner’s planets fall into. It shows the area of life where you feel each other most. Without a time there are no houses, and the book says so.
Tense does not mean bad
Squares and oppositions bring friction, and also movement. A couple with only harmonious aspects is often described as calm but without a spark. The book reads each aspect as a dynamic, not a verdict.