The Birth Chart

The wheel

The chart is a circle cut into twelve. Round the outside run the twelve signs, Aries through to Pisces, each one taking thirty degrees of the three hundred and sixty. The signs are the backdrop. They never move in relation to each other, and in every chart ever drawn they run in the same order, anticlockwise.

What changes from one chart to the next is where that backdrop sits against the horizon, and where the planets are standing in front of it.

The ten planets

Scattered round the wheel are the ten planets: the Sun, the Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. The Sun and Moon are called planets in astrology for convenience, and Pluto keeps its place whatever was decided in 2006. Each planet is placed at the exact degree of the sign it was in when you were born, so a chart might show the Sun at 14 degrees of Taurus, the Moon at 2 degrees of Scorpio, and so on round the wheel.

Each planet is a part of you. The Sun is your purpose, the Moon your feelings, Mercury your mind, Venus what you love, Mars how you fight. The sign a planet is in tells you how that part of you goes about its business. The Planets page introduces all ten.

The twelve houses

The wheel is also cut into twelve houses, and these are the part of the chart that depends on your birth time and place. The houses start from the eastern horizon and run anticlockwise round the chart, and each one is an area of life: the first house is you and your body, the second your money and possessions, the seventh your partnerships, the tenth your work in the world, and so on. A planet in a sign tells you how. A planet in a house tells you where.

The houses are not the same size as the signs. In the system I use, Placidus, they stretch and shrink depending on the latitude you were born at, so a sign can be swallowed inside one house, or a house can straddle two signs. I cross check every chart against Whole Sign houses as well, where each house is simply a whole sign. The Houses page explains both and what I do when they disagree.

The four angles

Four points on the wheel carry more weight than the rest. The Ascendant is the degree of the sign that was rising over the eastern horizon when you were born. It is the cusp, the starting line, of the first house, and its sign is your Rising sign. Opposite it, on the western horizon, is the Descendant, the cusp of the seventh house and the doorway to other people. The Midheaven, written MC from the Latin, is the highest point of the chart, the cusp of the tenth house, and it speaks to your public life and your work in the world. Opposite it sits the IC, the lowest point, the cusp of the fourth house, which is home, roots and the private self.

A planet sitting on an angle is loud. It colours the whole chart in a way the same planet tucked away in the middle of a house does not.

Why time and place matter so much

The signs and the slow planets barely change across a day. The angles and houses change constantly.

The Earth turns once in twenty four hours, which means the whole zodiac passes over the eastern horizon in a day. The Ascendant moves about one degree every four minutes, and a whole sign in roughly two hours. Two babies born in the same hospital four hours apart share a Sun sign, a Moon sign most of the time, and every outer planet, but they have different Rising signs, their planets fall in different houses, and their charts read quite differently.

So the time has to be good. I ask for it to within about fifteen minutes. "About 2 am" is a time of day, and it is not a birth time. A chart built on a guessed time is a different chart, and if the guess is off by an hour or more the Rising sign, the houses and the angles may all be wrong while looking perfectly convincing on the page. If your time is rough, say so, and treat everything that depends on it as provisional. Your Sun, your Moon and the aspects between the planets still stand.

The Moon is the one planet that can catch you out even with a rough time, because it moves about half a degree an hour and changes sign every two to two and a half days. Someone born on a day the Moon changed signs needs the time to know which Moon they have.

The time zone

The chart is built in the local time of the place where you were born, as the clocks actually stood on that day. If summer time was in force there, that counts. If the country has since changed its time zone, the chart still uses the zone that applied on your birthday, because that is the time written on your birth record and that is what the sky was doing when it was written.

This matters more than it sounds. An hour of clock time is about fifteen degrees of the zodiac at the Ascendant on average, which is half a sign, and a surprising number of charts drawn online are an hour out because the software guessed the wrong daylight saving rule for the year. A good chart names the time zone it used. Mine do.

The big three

The Sun, the Moon and the Ascendant are the three placements I look at first in any chart, and they are the three worth learning first in your own. The Sun is the life you are here to live. The Moon is what you need and how you feel. The Ascendant is how you arrive. Hold those three together and you have the skeleton of a person. The rest of the chart is flesh on it.

Reading the whole

A chart is not a list. People new to it tend to read it one line at a time, Sun in this, Moon in that, Venus in the other, and end up with a dozen descriptions that contradict each other. The chart reads as a whole or it does not read at all.

Start with the big three and see how they get on. Then look at where the planets are bunched and where the wheel is empty, which element and mode dominate, and which planets are talking to each other through aspects. A Mars that squares the Sun changes what that Sun means. A Venus alone in the twelfth house is a quieter Venus than the same Venus riding on the Ascendant. The meaning is in the relationships between the parts, and the only way to learn that is to sit with charts, your own first.

The chart is the stage and the season you were born into. What you do on it has always been up to you.

If you would like your own chart read, my readings are here.