The Birth Chart: How to Read It, Planet by Planet
The birth chart, or natal chart, is a map of the sky drawn up for a precise moment and place: the moment of your birth. It is the starting point of Western astrology. Reading a chart means observing the position of each celestial body in a sign and in a house, then the relationships between them.
What you need to draw it up
Three pieces of information are needed: the date, time and place of birth. The time matters a great deal, because it determines the ascendant, that is, the sign that was rising on the horizon at the moment of birth. Without a reliable time, you can still study the signs of the planets, but not the houses.
Software or a website now calculates the chart in a few seconds. In the past, astrologers used astronomical tables called ephemerides. The tradition goes back to antiquity: so-called horoscopic astrology took shape in the Greco-Roman world, from Babylonian and Egyptian sources.
The planets: the actors of the chart
According to this tradition, each body represents a psychological function or an area of life. Here are the most common reference points.
| Body | What it is associated with |
|---|---|
| Sun | identity, vitality, what you seek to become |
| Moon | emotions, habits, the need for security |
| Mercury | thought, communication, learning |
| Venus | tastes, affection, the way you love |
| Mars | energy, action, the way you assert yourself |
| Jupiter | expansion, optimism, confidence |
| Saturn | structure, limits, perseverance |
| Uranus, Neptune, Pluto | slow movements, associated with collective and generational change |
The sign shows how the body expresses itself: Mars in Aries is not described like Mars in Libra. The Sun is said to give the "engine", the Moon the "inner climate" and the ascendant the way you present yourself to others.
Houses and aspects
The sky is divided into twelve houses, which correspond to areas of existence: self-image, money, siblings, home, love, work, relationships, inheritances, travel, career, friendships, the unconscious. A planet placed in a house colours that area. Several systems of division exist (Placidus, whole signs, Koch), and astrologers do not agree on the best one.
Aspects are the angles formed between two bodies. The main ones are:
- the conjunction (0 degrees): two energies that merge;
- the sextile (60 degrees) and the trine (120 degrees): exchanges considered fluid;
- the square (90 degrees) and the opposition (180 degrees): tensions considered drivers of growth.
An astrologer never reads a single element in isolation. They look for repetitions, for example several planets in the same element (fire, earth, air, water) or in the same mode (cardinal, fixed, mutable).
How it is used today
Many people consult their chart out of curiosity, to put words to their personality, or as a prompt for reflection during a period of questioning. Some study it alone with online tools, others go to a professional astrologer. You can also compare two charts, which is called synastry, to talk about the dynamics of a couple or a friendship (see our compatibility tool).
For a first reading, a simple method is to note your Sun, Moon and ascendant, then read their descriptions as three facets of the same portrait. You then add the personal planets (Mercury, Venus, Mars), before tackling the houses and aspects.
Keep in mind that the birth chart has no demonstrated scientific validity: it is a symbolic language, which everyone interprets in their own way. For a broader presentation of the discipline, see the page devoted to astrology, or take a look at your daily horoscope.
Astrology is a matter of belief and entertainment, and it in no way replaces medical, legal or financial advice.