Two points sit 120° apart on a circle. One is the Ascendant, the degree of the zodiac climbing over the eastern horizon at your first breath. Astronomically it is the intersection of the ecliptic and the eastern horizon — which is why it shifts with both time and location, and why an accurate birth time is required to fix it. You can calculate yours with a rising sign calculator once you have that time.

The other point is Fortuna, a calculated place in the chart rather than a physical body. The Part of Fortune is derived from the Sun, Moon and Ascendant together. For day births the formula runs: Ascendant + Moon − Sun. Because the Ascendant is one of its three ingredients, Fortuna is personal in a way few points are. It is often described as the pulse of your material and social life, the spot where your body meets the world and things tend to land.

A trine is the 120° aspect — the widest, smoothest angle in traditional astrology. The measurement is simple: take two longitudes, subtract them, and reduce to the shortest arc on the 360° circle. If the result is about 120°, you have a trine. A separation of 122° is still a trine, carrying an orb of 2°. Anything close to exact reads with the most force, but even a loose trine keeps the same cooperative quality.