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Learn more about astrology: the birth chart explained piece by piece — the Sun, the Moon and the Ascendant across the twelve signs — and what changes when the three are read together.

Questions for people just starting out

The questions that come before the vocabulary — answered here with a calculation, not a memorised table.

The Sun in the 12 signs

The center of gravity of the chart: what your life is organized to develop.

The Moon in the 12 signs

What you need in order to feel safe — the part that shows up at home, and not at work.

The Ascendant in the 12 signs

The door of the chart: how you arrive, before any introduction.

The Sun in the 12 houses

The sign says how; the house says where. It is the piece that depends most on the exact time of birth.

The Moon in the 12 houses

The Sun says where you become who you are; the Moon says where you run when the day goes wrong.

The chart ruler in the 12 houses

The Ascendant is the door; its ruler is the address. It is the piece that depends on the time of birth twice over.

Mercury in the 12 signs

How you think and how you speak. Your Mercury can only be in three signs: your Sun's, the one before or the one after.

Venus in the 12 signs

How you love and what you find beautiful. Your Venus can only be in five signs: your Sun's, the two before it or the two after it.

Mars in the 12 signs

How you act, how you fight and how you go after what you want. It is the first piece of the chart that does not depend on your Sun: Mars can be in any of the twelve signs.

Jupiter in the 12 signs

Where you grow, where you overdo it and what life gives you for free. It is the first piece of the chart you share with everybody your age: Jupiter stays a year in each sign.

Saturn in the 12 signs

Where you take longer, where you are hard on yourself and what you build that lasts. It is Jupiter's pair and the widest piece of the chart: Saturn takes two and a half years in each sign, so this sign belongs to a whole cohort.

Uranus in the 12 signs

Where your generation broke the pattern. It is the least personal piece of the chart: Uranus takes seven years in each sign, so this sign belongs to a whole seven-year band — and what individualises it is the house.

Uranus in the 12 houses

Where your generation's rupture touches your own life. It is the half that individualises: the sign of Uranus belongs to a seven-year span, and the house depends on the exact hour.

Neptune in the 12 signs

What your generation idealised. It is an even less personal piece than Uranus: Neptune stays fourteen years in each sign, so this sign belongs to a whole span of fourteen years — and what individualises it is the house.

Neptune in the 12 houses

Where your generation's ideal touches your life. It is the half that individualizes: the sign of Neptune covers a fourteen-year span, and the house depends on the exact hour.

Pluto in the 12 signs

What your generation had to remake. It is the least personal piece of all: Pluto stays between twelve and thirty-one years in each sign, so this sign belongs to a whole span of people — and what individualises it is the house.

Pluto in the 12 houses

Where your generation's transformation touches your life. It is the half that individualizes: the sign of Pluto covers a wide span, and the house depends on the exact hour.

The Vertex in the 12 signs

The piece of the chart that depends most on WHERE the person was born. Inside the tropics the Vertex only falls in two short, opposite arcs — in Belém, seven degrees each — and that is why four signs are possible at any latitude and the last two only exist beyond 23.4381 degrees, which is the tilt of the Earth.

The Part of Fortune in the 12 signs

The piece that is neither a body nor an angle: it is a calculation made from the Ascendant, the Sun and the Moon. Its arc to the Ascendant is the Moon phase you were born under — and the formula changes between day and night, which changes the sign in 91.8% of charts.

Lilith in the 12 signs

The point in the chart where a person does not bend — and the only one that treats all twelve signs exactly alike: 269.3 days in each. With the fact almost no site mentions: there are two Liliths, and they disagree about the sign in more than one chart out of three.

Lilith in the 12 houses

Where the untameable in your chart touches your life. The sign of Lilith depends on which of the two your software computed — they disagree on 36.4% of days; the house comes from the time and the place, and shares out evenly.

The Midheaven in the 12 signs

The piece that says what people see you doing — and the only one of the four angles that does NOT depend on the city. The Ascendant changes with the place; the Midheaven, only with the clock.

Chiron in the 12 signs

The one point in the chart that spends eight years in one sign and less than two in another — the orbit is lopsided, and that changes what the placement means. Every page carries the measured time and the dates.

Chiron in the 12 houses

Where your cohort’s learning touches your life. The sign of Chiron is a cohort running from 1.70 to 8.00 years depending on the sign; the house shares out evenly and depends on the exact time.

The lunar nodes in the 12 signs

The axis the eclipses mark: on one side what you already do far too well, on the other the direction with no practice. Every page describes both ends, because they do not come apart.

The aspects between the planets

The distance in degrees between two pieces of the chart, and what it does to both. Eleven of the 225 combinations do not exist — and this series says which, with the number.

Mercury in the 12 houses

The sign says HOW you think; the house says WHERE that mind works. It is the piece that requires the exact time of birth.

Venus in the 12 houses

The sign says HOW you love; the house says WHERE the affection happens. It is the piece that requires the exact time of birth.

Mars in the 12 houses

The sign says HOW you fight; the house says WHERE the force is spent. It is the piece that needs the exact hour of birth.

Jupiter in the 12 houses

The sign of Jupiter belongs to your whole age group; the house is yours alone. This is where the reading stops being about a generation and starts being about you.

Saturn in the 12 houses

Where life makes its demands of you, and where what you build is not lost. It is the half that is yours: the sign of Saturn belongs to a whole two-and-a-half-year cohort, and the house depends on the hour of your birth.