Natal chart
A map of the sky for the exact moment and place of a birth: every planet's position, the rising degree, the houses. It is the fixed reference that all timing techniques compare against.
A natal chart, or birth chart, is a diagram of the sky as seen from your birthplace at your moment of birth. It records where the Sun, Moon, and planets stood along the ecliptic, measured in degrees of the zodiac, together with computed points like the Ascendant, the Midheaven, and the lunar nodes.
Each layer answers a different question. Planets are the actors: which part of life is speaking. Signs describe manner: how that actor behaves. Houses supply the setting: where in life the action lands. Aspects, the angles between planets, describe how the actors get along. Reading a chart is the craft of holding those four layers together.
Precision matters more than mystique here. A birth date pins the planets down well enough, but the Ascendant and the houses turn with the Earth, shifting about a degree every four minutes. That is why a reliable birth time is worth chasing, and why, when the time is unknown, we cast a noon chart and set the houses aside rather than guess.