What is a birth chart and how do you read one as a beginner?

A birth chart is the sky at one birth: the Sun, the Moon, and the planets, set in the 12 signs and against the local horizon. A beginner reads that picture in order, from the bodies and their signs, to the houses, to the aspects, and brings one question the picture can organize.

In Tetrabiblos III.1, Ptolemy names this branch Genethlialogy, the science of nativities, and he traces a particular person's events to the configuration at birth. See a doctor, a lawyer, an adviser, or a therapist for health, legal, money, and mental-health decisions. A chart can organize a choice you can already describe.

What is a birth chart?

A birth chart is a calculated figure of the heavens for one recorded time and place. In Tetrabiblos I.1, Ptolemy tells Syrus that the studies preliminary to astronomical prognostication are two. The first leads to the figurations of the Sun, the Moon, and the stars, and to their relative aspects to each other and to the earth. The second considers the changes those aspects create, through the bodies' own properties, in whatever they act on.

He sets the two studies apart. The first follows immutable laws. For the second, the material is variable and hard to apprehend exactly, so no positive or infallible rules can be set forth there. A beginner chart belongs to that second study: positions you can check, read beside a question.

Tetrabiblos III.2 says the natural start is the conception, and the birth is the moment to use when that earlier time is unknown. He calls the conception the generation of the seed and the birth the generation of the person. A chart on this site is cast for the birth date, clock time, and place you record.

Which planets and angles does a birth chart record?

A birth chart records where each body stood along the zodiac, and where the local horizon stood. Tetrabiblos I.4 gives seven bodies by quality: the Sun produces heat and moderate dryness, the Moon principally generates moisture, Saturn produces cold more than dryness, Mars causes dryness and strong heat, Jupiter is temperate with warmth predominant, Venus is temperate with moisture predominant, and Mercury produces dryness and moisture by turns.

This site's chart places those seven and also places Uranus, Neptune, Pluto, and the True Node. The four angles locate the horizon. Tetrabiblos I.13 calls them the four cardinal points: the eastern angle of the ascendant, the southern angle of the mid-heaven, the western or occidental angle, and the northern angle of the lower heaven. On this site those four are the Ascendant, the Midheaven, the Descendant, and the Imum Coeli. In Tetrabiblos I.15 the ascending sign is also called the horoscope, meaning the Ascendant's sign.

A chart cast for 6:30 a.m. on June 6, 1944, in the Europe/London zone, at latitude 50.7184 north and longitude 1.8808 west, has its Universal Time at 4:30. The Sun stands at 15.3 degrees of Gemini. The Moon stands at 7.8 degrees of Sagittarius. The Ascendant stands at 22.4 degrees of Gemini. The Midheaven stands at 17.6 degrees of Aquarius.

How are the 12 signs divided on a birth chart?

The 12 signs are 12 successive spans of the zodiac. Just before Tetrabiblos I.14, Ptolemy says the general temperaments of the signs are analogous to the seasons established under each sign. In I.14 the tropical signs are the first 30 degrees after the summer solstice, which compose Cancer, and the first 30 degrees after the winter solstice, which compose Capricorn. The equinoctial signs are Aries, the first after the vernal equinox, and Libra, the first after the autumnal equinox, where he says the Sun makes day and night equal.

A placement is a sign plus the degrees already traveled inside it. In the June 6, 1944 chart, the Sun at 15.3 degrees of Gemini sits 15.3 degrees from the start of Gemini, and the same reading fixes the Moon in Sagittarius and the Ascendant in Gemini.

How do houses and aspects change a placement?

Houses locate a body against the horizon. Aspects name the angle between two points. A birth chart has 12 houses. This site follows Placidus because the First House cusp is the Ascendant and the Tenth House cusp is the Midheaven, and the cusps between those angles are set along the arcs with the birth latitude, so a house can open in the middle of a sign. Another common approach, Whole Sign, starts the First House at the beginning of the Ascendant's sign and gives one sign to each house after it.

In the June 6, 1944 chart the Ascendant is in Gemini, so under Whole Sign Gemini is the First House, Cancer the Second House, and Leo the Third House. Jupiter stands at 21.2 degrees of Leo. Under Placidus the Fourth House cusp, the Imum Coeli, falls at 17.6 degrees of Leo, and the Fifth House cusp falls at 16.9 degrees of Virgo, so Jupiter is in the Fourth House. Under Whole Sign the same Jupiter is in the Third House. Read the house system named on the chart.

Tetrabiblos I.16 gives four distances between parts of the zodiac: the opposition at 180 degrees, or six signs; the trine at 120 degrees, or four signs; the quartile at 90 degrees, or three signs; and the hexagonal distance at 60 degrees, or two signs. He calls the trine and the sextile harmonious, because they join signs of the same kind. He calls the opposition and the quartile discordant, because they join signs of different kinds. Ashmand's note on this chapter records that Whalley was surprised the conjunction is missing, and answers that the chapter treats parts configured with each other, so a part is not configured with itself.

On this site the five aspects are the Conjunction at 0 degrees, the Sextile at 60, the Square at 90, the Trine at 120, and the Opposition at 180. Ashmand's quartile is the Square, and his hexagonal distance is the Sextile. The allowance is 8 degrees when the Sun or the Moon is one of the points, 6 degrees between other planets, and 4 degrees when an angle is one of the points. In the June 6, 1944 chart the Sun and the Moon stand 172.5 degrees apart, 7.5 degrees from an exact Opposition, inside the 8-degree allowance.

How does a beginner read a birth chart in order?

Write the birth date, the clock time, and the place, including the time zone. Tetrabiblos III.3 says the minute of the hour usually needs a careful observation, because a water clock can flow unevenly and a sundial can sit off the true meridian. Keep an uncertain minute as a range. How to rank a remembered hour against a written record is in what birth information a reading needs.

Name the Sun's sign, the Moon's sign, and the Ascendant's sign, then the house of each body under the system the chart names, then the Conjunction, Sextile, Square, Trine, and Opposition. A personal reading calculates the chart from the date, clock time, and place you provide and leaves those positions on the page.

What question should you bring to a birth chart?

Bring one sentence with four parts: the background you already know, the options that are open, the time range, and the judgment you want. The sentence shape is in how to turn a vague worry into a question a reading can answer. For a chart it might name a June review at work, the choice to stay or to ask for a different project, and the pattern to watch until that review.

How to turn a prediction into a useful reflection keeps a calculated position separate from a life claim you can later check. To keep a reading for two years and ask follow-up questions on the same chart, see pricing.

FAQ

What is a birth chart?

A birth chart is the Sun, the Moon, and the planets in the signs and on the local horizon at one birth. Ptolemy calls that branch Genethlialogy, the science of nativities, and the chart beginners use is cast for the recorded birth.

What does a beginner read first on a birth chart?

A beginner writes the date, the clock time, and the place, then names the Sun, the Moon, and the Ascendant, then the houses in the named house system, then the aspects, then one question.

Does every house system put Jupiter in the same house?

No. In the June 6, 1944 chart, Jupiter at 21.2 degrees of Leo is in the Fourth House under Placidus and in the Third House under Whole Sign.

Where do health and legal questions belong?

See a doctor, a lawyer, an adviser, or a therapist. A birth chart organizes a choice you can already describe.