What is a birth chart?

A diagram of where the Sun, Moon and planets stood along the zodiac at the moment and place of a birth, with the horizon and the point overhead marked. The positions are astronomy; the reading is what astrology adds to them.

Do I need my birth time?

For the signs of the Sun and most planets, the date is enough, though the Moon changes sign every two or three days and can need the hour. For the rising sign and the houses, the time is needed, because the horizon moves a degree about every four minutes. Without it, the planets keep their signs and lose their houses.

How do I read my own chart?

Start with the Sun, Moon and rising sign, then take each planet as a sentence: the planet is the function, its sign the manner, its house the area of life. Then the aspects, which say how two of them combine. The calculator lays all of it out from your birth data.

Astrology basics: signs, planets, houses and aspects

A birth chart is a map of the sky at the minute and place of a birth: where the Sun, Moon and eight planets stood along the zodiac, and which part of that sky was rising, overhead and setting from there. This section explains the pieces. Nothing here interprets anyone; the calculator does that from a chart.

Planets in signs in houses

A chart reads as a sentence of three parts. The planet is the function: the Sun is what a person is for, the Moon how feeling settles, Mercury how they take in and say things. The sign says how that function works, its manner. The house says where in life it is applied. Mars in Virgo in the 6th is one planet read three times: the pursuit of a want (Mars), done in a checking, exacting way (Virgo), at work and in the daily routine (the 6th).

Aspects are the fourth part: angles between planets, how two functions combine.

The twelve signs

A sign is a twelfth of the Sun's yearly path through the sky, thirty degrees of the zodiac. Every planet is in a sign at any moment, so a person has a Moon sign and a Mercury sign as well as the Sun sign the newspaper uses. Each sign's page gives its element, modality, ruling planet, the Sun's approximate dates in it, and what it does to a planet in it.

The ten planets

The site reads ten bodies: the Sun and Moon, planets by astrology's long habit, and Mercury through Pluto. Each has a cycle, from the Moon's month to Pluto's two and a half centuries, and a domain. The fast ones describe the person; the outer three move so slowly that a sign placement describes a generation.

The twelve houses

A house is a twelfth of the sky as seen from the birthplace, counted from the eastern horizon, which is why houses need a birth time: the horizon moves a degree about every four minutes. The houses are areas of life, from the 1st (how someone arrives) to the 12th (what they do unseen).

The five aspects

An aspect is an angle between two planets, measured along the zodiac. Five are read here: the conjunction at 0 degrees, the sextile at 60, the square at 90, the trine at 120 and the opposition at 180, each with an orb, a tolerance inside which it still counts. Each page says what the angle does, natally and in transit.

Questions

What is a birth chart?: A diagram of where the Sun, Moon and planets stood along the zodiac at the moment and place of a birth, with the horizon and the point overhead marked. The positions are astronomy; the reading is what astrology adds to them.
Do I need my birth time?: For the signs of the Sun and most planets, the date is enough, though the Moon changes sign every two or three days and can need the hour. For the rising sign and the houses, the time is needed, because the horizon moves a degree about every four minutes. Without it, the planets keep their signs and lose their houses.
How do I read my own chart?: Start with the Sun, Moon and rising sign, then take each planet as a sentence: the planet is the function, its sign the manner, its house the area of life. Then the aspects, which say how two of them combine. The calculator lays all of it out from your birth data.

Calculate your birth chartFree, with a reading, from your date, time and place. Nothing stored.