Skip to content

A living tradition · Hellenistic, about 2,100 years old as a chart

Natal Chart (Tropical)

The sky at the moment and place of birth, as the Western tradition draws it

Where the Sun, the Moon and each planet stood when you were born, by sign and by house, and the angles they make with one another.

Draw your free chart: natal chart No email needed
Get the reading · $3.99 for Natal Chart

Your Natal Chart reading, $3.99. Includes this system's raw data. Written for you by AI. Read a sample. Charts and the written text are free in every account.

Your natal chart is drawn for the minute and place you were born, as a wheel: for 19 January 1989 at 19:17 in Ann Arbor it puts Leo on the rising degree, the Sun in the last degree of Capricorn in the sixth house, the Moon in Cancer in the eleventh, and lines across the centre for the aspects.

The chart is Hellenistic, put together in Egypt in the last two centuries BCE and handed on through Arabic and Latin textbooks to the astrology of today.

A natal chart wheel with the Ascendant at the left, in 21°03′ Leo, and the zodiac running counter-clockwise; Placidus house cusps; Sun 29°55′ Capricorn, house 6; Moon 7°47′ Cancer, house 11; Mercury 10°23′ Aquarius, house 6; Venus 11°35′ Capricorn, house 5; Mars 0°22′ Taurus, house 9; Jupiter 26°05′ Taurus, house 10; Saturn 7°47′ Capricorn, house 5; Uranus 2°51′ Capricorn, house 5; Neptune 10°37′ Capricorn, house 5; Pluto 14°57′ Scorpio, house 4; Chiron 2°41′ Cancer, house 11; North Node 5°18′ Pisces, house 7. Lines in the centre join 13 pairs of bodies in aspect. ♈︎ ♉︎ ♊︎ ♋︎ ♌︎ ♍︎ ♎︎ ♏︎ ♐︎ ♑︎ ♒︎ ♓︎ 1 2 3 4 5 6 7 8 9 10 11 12 ☊︎ ♂︎ ♃︎ ⚷︎ ☽︎ ⯓︎ ♅︎ ♄︎ ♆︎ ♀︎ ☉︎ ☿︎ AC

Solid: squares and oppositions. Dashed: trines and sextiles.

The big three

  • Sun 29°55′ Capricorn in the 6th house (Placidus)
  • Moon 7°47′ Cancer in the 11th house (Placidus)
  • Rising 21°03′ Leo

Chart ruler

The Sun, ruler of Leo, in 29°55′ Capricorn.

The Moon's phase

Gibbous, in Rudhyar's eight phases; 96 percent lit. A night chart: the Sun is 19° below the horizon.

The five closest aspects

  • Moon opposition Saturn 0°01′, exact
  • Uranus opposition Chiron 0°10′, exact
  • Sun square Mars 0°27′, applying
  • Venus trine Midheaven 0°44′
  • Venus conjunction Neptune 0°57′, separating
Figure 1. The natal chart of a fictional person born on 19 January 1989 at 19:17 in Ann Arbor, Michigan, with Placidus houses: Leo rising, the Sun in the last degree of Capricorn in the sixth house, the Moon in Cancer in the eleventh. Lines in the centre join the bodies in aspect, solid for squares and oppositions, dashed for trines and sextiles; conjunctions show by closeness. Beside it, the big three, the chart ruler, the Moon's phase in Rudhyar's scheme and the five closest aspects. Method: positions from NASA JPL's DE440s through Skyfield; Placidus houses; the true node; orbs of 10° (6° sextile, 3° quincunx) with the Sun or Moon in the pair, 8°, 4° and 2° otherwise, half to Chiron, the node and the angles. The full chart, with Whole Sign and Equal houses and every aspect, is one tap away.
On this page
  1. How it works
  2. Origins and history
  3. The signs, bodies, points, houses and aspects
  4. Variants and what we leave out
  5. Myths and disputed claims
  6. Stories and lore
  7. Evidence and criticism
  8. Terms
  9. Sample reading
  10. Sources

How it works

A natal chart is a map of the sky for one moment, seen from one place: the moment of a birth and the place it happened. The tradition draws it as a wheel. Around the rim run the twelve signs of the zodiac; inside, the twelve houses divide the sky as it stood above and below the local horizon; the Sun, the Moon and the planets sit at their positions; and lines across the middle join the pairs that stand at certain angles to one another, the aspects.

A woodcut of a bedroom. In front, a woman sits on a low birthing stool, held from behind by one woman while a midwife kneels before her and a third woman leans in. Behind them, through an arched window full of stars and a crescent moon, one man points at the sky while another, seated at a table, draws a square chart.
Figure 2. A woodcut of a birth, which the Wellcome Collection dates 1583 with a query and credits to no artist: a midwife and two women attend a mother on a birthing stool while, at the window behind, two men read the night sky and one draws a square chart on the table. The scene is the whole idea of the natal chart: the sky noted for the moment and place a life begins. 1583 (the holder's date, queried). Wellcome Collection, Public Domain Mark 1.0.

The signs. The zodiac is the band of sky along the ecliptic, the Sun's yearly path, cut into twelve equal signs of 30°. The tropical zodiac counts them from the March equinox: 0° Aries is where the Sun stands as northern spring begins, and each sign keeps its place in the seasons. The signs take their names from constellations near them but are not the constellations, which are star figures of unequal size. The equinox also slides slowly against the stars, about 1° in 72 years, the drift astronomers call precession, so a zodiac counted from the stars now differs from ours by about 24°.

The planets. In the tradition's usage "the planets" are the Sun and Moon, the two luminaries, with Mercury, Venus, Mars, Jupiter and Saturn, the five known since antiquity. Modern astrology added Uranus (found in 1781), Neptune (1846) and Pluto (1930). We also show Chiron, a small body found in 1977, and say that it is a modern addition.

The houses. The houses turn with the Earth. They are counted from the Ascendant, the degree of the zodiac rising in the east at the moment of birth, which moves about a degree every four minutes; this is why the chart needs a birth time and a place. Opposite the Ascendant sets the Descendant; the Midheaven is the degree culminating on the meridian, and the IC lies opposite it. How the sky between these four angles is divided has many answers. We use Placidus by default and offer Whole Sign and Equal houses with one tap; above the polar circles, where Placidus cannot be computed, we use Porphyry and say so on the chart.

The aspects. Two bodies are in aspect when the angle between them along the zodiac is close to one of the classic distances: 0° (conjunction), 60° (sextile), 90° (square), 120° (trine) or 180° (opposition). The chart also lists the 150° quincunx. How close counts is the orb, and orbs differ from school to school. Ours are 10° for a conjunction, square, trine or opposition, 6° for a sextile and 3° for a quincunx when the Sun or Moon is one of the pair, and 8°, 4° and 2° otherwise; Chiron, the North Node, the Ascendant and the Midheaven take half of these, and never from one another. Within a quarter of a degree an aspect is marked exact, and each is labelled applying or separating from the two speeds.

The points. The lunar nodes are where the Moon's path crosses the ecliptic; we show the true North Node, labelled, and the South Node opposite it. Lilith, in our chart, is the mean apogee of the Moon's orbit, an empty point and not a body. The Part of Fortune is a lot counted from the Ascendant: Ascendant plus Moon minus Sun by day, reversed by night, with day and night decided by the Sun's height above the horizon at the birth place. The Vertex is a twentieth-century point where the prime vertical meets the ecliptic in the west. The South Node, Lilith, the Part of Fortune and the Vertex take no aspects.

How we compute it. The birth date, the clock time to the minute, the place's latitude and longitude and the time zone in force there at the time (from the IANA history) give one instant in universal time. The engine reads apparent positions from NASA JPL's DE440s ephemeris through the Skyfield library, with the IAU 2000A nutation, and interpolates Chiron from JPL Horizons. In our validation over 56 births every planet fell within 0.7 arc second of an independent computation, the same class of accuracy as the software most astrologers use, and the houses, points and aspects followed the stated conventions. Those checks show that the positions match astronomy. They say nothing about whether a chart describes anyone; that question is under Evidence and criticism below.

Without a birth time the chart is cast for noon and says so. The Moon can then be as much as 7° from where it really was, so its sign is uncertain when it sits near a boundary, and there is no Ascendant, no Midheaven and no houses to read.

What else the chart names. The chart ruler, which is the traditional ruler of the rising sign, with the modern co-ruler named beside it for Scorpio, Aquarius and Pisces; whether the birth was by day or by night; the Moon's phase as one of the eight phases Dane Rudhyar named in The Lunation Cycle (1967), labelled as his; each body's decan, and whether it is out of bounds, beyond the Sun's farthest declination; and the traditional dignities of the seven classical planets: domicile, exaltation, detriment and fall. The readings beside the chart are EsoTerrier's own words, written in 2026 from the shared symbolism of the tradition, and they describe tendencies, never events.

Origins and history

The chart as we draw it is about 2,100 years old; its pieces are older. Babylonian scribes recorded sky omens for their kings, divided the ecliptic into twelve equal signs about 400 BCE and cast the first birth horoscopes; in Ptolemaic Egypt, in the last two centuries BCE, these met the Egyptian decans and Greek geometry, and the result was a chart counted from the rising degree. The tradition passed through Greek, Arabic and Latin textbooks to the Renaissance, lost its place in the universities, and was remade twice in the twentieth century, first as an astrology of character and then by a revival of the old texts.

When Who What happened
2nd millennium BCE Babylonian scribes Celestial omens for the king and the state are gathered in the series Enuma Anu Enlil; the star catalogue MUL.APIN follows about 1000 BCE.
29 April 410 BCE A Babylonian scribe The oldest surviving birth horoscope: a clay tablet listing the planets' positions for a birth. Such texts run on to the 1st century BCE.
409 to 398 BCE Babylonian astronomers The ecliptic is divided into twelve equal signs of 30°, probably within a few years of 401 BCE: the uniform zodiac that both later zodiacs inherit.
2nd century BCE Hipparchus Finds that the equinox moves against the stars by comparing Spica with older records: precession, now known to run about 1° in 72 years.
Late 2nd to 1st century BCE Authors writing under the names Hermes, Nechepso and Petosiris In Ptolemaic Egypt the Babylonian zodiac, the Egyptian decans and Greek geometry become horoscopic astrology: the horoskopos, or hour-marker, and the twelve places counted from it, the aspects and the lots.
1st century CE Dorotheus of Sidon; Marcus Manilius Dorotheus's verse textbook, which survives in Arabic, and Manilius's Latin poem Astronomica.
About 152 to 188 CE Vettius Valens The Anthologies, the largest practitioner's book of the tradition, with more than a hundred example charts; the source of the day and night reversal of the Lot of Fortune.
2nd century CE Claudius Ptolemy The Tetrabiblos gives the tradition its best-known rationale, from Aristotelian physics, and counts the zodiac from the equinox; the planets' natures, the aspects and the dignities.
4th century CE Julius Firmicus Maternus The Mathesis, eight books in Latin, among the late-antique textbooks.
8th to 11th century Masha'allah, Abu Ma'shar, al-Biruni and others The Arabic synthesis of Greek, Persian and Indian astrology; Abu Ma'shar's Great Introduction (848) argues for astrology on Aristotelian principles.
1133 to 1140 John of Seville, Hermann of Carinthia, Plato of Tivoli Latin translations of Abu Ma'shar and of the Tetrabiblos bring the tradition back to Europe.
About 1277 Guido Bonatti The Liber Astronomiae, the largest Latin textbook of the 13th century; Dante puts its author in the Inferno.
1496 Giovanni Pico della Mirandola The Disputationes adversus astrologiam divinatricem, the Renaissance's great attack on judicial astrology, published after his death.
1601 to 1619 Johannes Kepler Argues for a reformed astrology of aspects in three books and adds new aspects, such as the quintile; casts more than 800 horoscopes.
1602; 1650s Giovanni Antonio Magini; Placidus de Titis The first confirmed publication of the house division later named for Placidus, who promoted it.
1647 William Lilly Christian Astrology, the English textbook of the tradition, with the houses, orbs and dignities.
18th century Astrology leaves the universities as Newtonian science removes its rationale.
1890s to 1917 Alan Leo Modern Astrology and a long run of textbooks; turns the reading of a chart from events to character; convicted of fortune-telling in 1917.
24 August 1930 R. H. Naylor, Sunday Express A horoscope for the newborn Princess Margaret leads to Britain's first regular newspaper astrology column.
1936 Dane Rudhyar The Astrology of Personality: astrology as insight rather than prediction, drawing on Jung's psychology.
1952 C. G. Jung Publishes a statistical experiment on married couples' charts and judges it inconclusive.
1960s; 1971 Walter Koch The Koch house system; its tables appear in English in 1971.
1976 Liz Greene Saturn: A New Look at an Old Devil; with Howard Sasportas she later founds the Centre for Psychological Astrology.
1 November 1977 Charles Kowal Announces the discovery of Chiron; astrologers take it up in the 1980s.
1985 Olivia Barclay; Shawn Carlson A facsimile of Lilly's Christian Astrology starts the traditional revival in Britain; in Nature, a double-blind test of astrology.
1993 Robert Schmidt, Robert Hand, Robert Zoller Project Hindsight begins translating the Greek and Latin sources; whole-sign houses and the lots return to practice.
2017 Chris Brennan Hellenistic Astrology, the survey that took the revival to a wide readership.
2021 Ryan Park and colleagues at JPL The DE440 and DE441 ephemerides, the planetary data our engine reads.
2026 EsoTerrier The chart rebuilt: positions validated to under one arc second, the Vertex and the Part of Fortune corrected, house systems and the mean points added.
An engraved oval portrait of three men: in the middle a clean-shaven man with long hair and a white collar, William Lilly; on the left a bearded man in a fur cap, on the right a bearded man in a turban. Beneath, in an ornamented panel, four lines of verse in italic script.
Figure 3. William Lilly between two older authorities, the frontispiece of Anima Astrologiae (London, 1676), Guido Bonatti's considerations and Cardano's aphorisms in English, edited under Lilly's name with a preface by Henry Coley (Wellcome Collection). The verse below says that to "Cardan & to Guido much is Due, / But in one Lilly wee behold them Two": the English tradition presenting itself as the heir of the medieval and Renaissance authors. 1676. Wellcome Collection, Public Domain Mark 1.0.

The line from Leo to Rudhyar matters for how the chart is read today. Leo argued in court in 1917 that he described tendencies, not events; Rudhyar built an astrology of personality on that turn and on Jung's ideas; Liz Greene's generation made it the mainstream. Jung himself used horoscopes in his practice but founded no school of astrology. The revival since 1985 reads the old texts again, and whether the psychological or the traditional reading is the true art is still argued.

The signs, bodies, points, houses and aspects

Each has its own page: what it is, how it is computed, how Ptolemy, Valens, Lilly and the modern schools read it, our own keywords labelled as ours, and the claims made about it. They are listed in the engine's order, by kind. The planet-in-sign and planet-in-house readings are in the chart itself.

Variants and what we leave out

The commonest question about any birth chart is why two tools give different charts. The answer is almost always one of these conventions.

  • House systems. Whole Sign is the oldest, the Hellenistic places, in disuse in the West from about the 10th century and revived since the 1980s and 1990s. Equal houses divide from the Ascendant; Porphyry, first described by Valens, and Alcabitius trisect the quadrants; Campanus and Regiomontanus divide space; Placidus and Koch divide time. Placidus is the most used in modern Western astrology, Koch is popular among German speakers, and Whole Sign leads in the Hellenistic revival. We default to Placidus, offer Whole Sign and Equal, fall back to Porphyry above the polar circles, and have left Koch, Regiomontanus, Campanus and Alcabitius out for now. A planet can change house between systems: between Placidus and Whole Sign a median of twelve of sixteen objects moved in our test charts.
  • Tropical or sidereal. Western astrology counts the signs from the equinox; Jyotisha, and the Western sidereal school of Cyril Fagan and Donald Bradley, count them from a point among the stars, about 24° back by Lahiri's measure in 2026, the Indian national standard fixed by the Calendar Reform Committee of 1955. Neither is the "real" sign: they measure the same sky from different starting points, and many tools offer both. We draw the Jyotisha chart separately, with its square layout, whole-sign houses, nine grahas and nakshatras. The oldest surviving Sanskrit horoscopy, the Greek-derived Yavanajataka, has been redated by Bill Mak to after 22 CE and possibly as late as the early 7th century.
  • The node. True (osculating) or mean: astro.com shows the true node, Astro-Seek and the Indian ephemerides the mean, and the two differ by up to about 2°. We show the true node, labelled "(true)", and use the mean node in the Jyotisha chart.
  • Lilith. Three things carry the name: a second moon that Georg Waltemath claimed in 1898, which Sepharial called Lilith in 1918 and which was never confirmed; the asteroid 1181 Lilith, found in 1927; and the Black Moon, the Moon's apogee, an empty point whose French name Lune noire goes back to Dom Neroman's book of 1937. The apogee comes as a mean point and an osculating ("true") one that swings about 30° around it. We show the mean apogee as "Lilith (mean)" and compute neither the asteroid nor the hypothetical moon.
  • The Part of Fortune. Ptolemy used the day formula "both by night and day" (Tetrabiblos III.13, in Ashmand's 1822 translation), and Lilly did the same in 1647; Valens and Dorotheus reversed it for night births, as astro.com does by default. We reverse at night, decide day or night by the Sun's altitude, and name the formula used.
  • The Vertex. A twentieth-century point: Charles Jayne, testing L. Edward Johndro's "electrical ascendant", found the opposite point more sensitive, and Johndro confirmed it before he died in November 1951. Neither astro.com nor Astro-Seek draws it by default; we show it in the table and with the points toggle.
  • Chiron and the asteroids. Some schools use Ceres, Pallas, Juno, Vesta and the other centaurs. We show Chiron and no other small body.
  • Orbs. Lilly gave each planet its own orb and counted an aspect as begun within half the sum of the two, "the moyity of both their Orbs" (1647). astro.com's default is a flat 10°, 6° for the sextile; its classical style and the Astrowiki scale the orb by planet; CHANI counts aspects by whole sign. Ours, chosen in 2026 to cut clutter, sits between the flat and the classical styles and is printed with every chart.
  • Minor aspects. Kepler's quintile and biquintile, the semi-sextile, the semi-square and the sesquiquadrate. We compute the quincunx and no other minor aspect.
  • Rulers. The traditional seven rulers, with Uranus, Neptune and Pluto as modern rulers of Aquarius, Pisces and Scorpio. That came in stages: John Varley gave Uranus Aquarius in 1828, Alan Leo in 1899 still wrote of Neptune as "supposed to govern Pisces", and Pluto was listed for Scorpio by 1936; the traditional revival keeps the old rulers. We name the traditional ruler as chart ruler and the modern co-ruler beside it.
  • Techniques we do not compute. Transits, progressions, solar returns, synastry, midpoints, the other lots, zodiacal releasing and annual profections, fixed stars, and the term and face dignities. The Sabian symbols and the draconic chart are separate pages built on the same positions.

Myths and disputed claims

The chart attracts more confident claims than any other system on this site, from both its friends and its critics. Each card gives the claim, who makes it and what the record shows; the full list is in our research.

A hand-coloured octagonal star chart crowded with constellation figures in yellow, red, green and blue: a lion, a crab, twins, a bull, a ram, a whale, river figures, a ship, bears and human figures, set round the north pole, with a curved band marked Ecliptica and a degree scale round the rim.
Figure 4. The northern sky in Petrus Apianus's Astronomicum Caesareum (Ingolstadt, 1540), woodcuts from Michael Ostendorfer's workshop, coloured by hand (the Metropolitan Museum of Art). The figures of the zodiac constellations, the Ram, the Bull and the rest, stand along the band marked ecliptica at very different sizes: the star figures the signs are named after, but not the signs themselves, which are twelve equal parts of the ecliptic. 1540. The Metropolitan Museum of Art, CC0 1.0.

  • Astrology is 5,000 years old.

    disputed

    Who says it: Popular histories, app copy and some practitioners' books.

    What the record shows: Omens are recorded from the 2nd millennium BCE, but the twelve equal signs date from about 400 BCE, the oldest birth horoscope from 410 BCE and the chart with an Ascendant and houses from the 2nd or 1st century BCE: about 2,100 years.

  • Nechepso, Petosiris and Hermes Trismegistus invented horoscopic astrology.

    told as lore

    Who says it: Firmicus Maternus in the 4th century, the Hellenistic texts themselves and many sites.

    What the record shows: The texts under these names were written in Ptolemaic Egypt in the 2nd or 1st century BCE. The art did arise there, from Babylonian, Egyptian and Greek pieces; its named founders are literary.

  • Ptolemy purged astrology of superstition and made it a rigorous science.

    disputed

    Who says it: Popular accounts of the Tetrabiblos.

    What the record shows: He gave the tradition its best-known rationale, from Aristotelian physics, and left out much of the lot-based practice; but he was one author among several, and the practitioners' tradition went on beside him.

  • Kepler validated the aspects, proving that harmonious angles act on the air and the mind.

    false

    Who says it: Popular histories of astrology, and our retired page writer.

    What the record shows: Kepler argued for a reformed astrology of aspects in 1601, 1610 and 1619 and added new aspects of his own. He proposed; he did not prove, and he mocked much of the practice he was paid for.

  • Carl Jung created psychological astrology.

    false

    Who says it: Blogs and marketing that lean on his name.

    What the record shows: Alan Leo turned the reading of charts towards character before 1917; Dane Rudhyar built on Jung's ideas from 1936; Liz Greene and others made it the mainstream from the 1970s. Jung used horoscopes in his practice but founded no school of astrology.

  • The twelve signs are the twelve constellations, each 30° wide.

    false

    Who says it: Beginners' pages and some school textbooks.

    What the record shows: The signs are equal divisions of the ecliptic; the constellations are star figures of different sizes, and by the boundaries astronomers drew in 1930 the Sun crosses thirteen of them. The names were shared from the start, the shapes never.

  • There is a thirteenth sign, Ophiuchus, and everyone's sign has moved.

    false

    Who says it: Books of 1970 and 1995, and the viral stories of 2011 and 2016.

    What the record shows: The tropical signs are twelve equal divisions counted from the equinox and were never the constellations. Ophiuchus is a constellation the ecliptic crosses, not a sign of either zodiac in use.

  • NASA changed the zodiac.

    false

    Who says it: Viral articles of September 2016, revived in 2020.

    What the record shows: NASA's own post of 20 September 2016 said it had changed no zodiac signs and had only done the math, after a page for children explained precession. NASA does not define the zodiac.

  • Tropical astrology is wrong because its signs no longer match the constellations.

    false

    Who says it: Sidereal advocates, sceptics' pages, and our own old comparison table.

    What the record shows: The tropical zodiac is defined from the March equinox and keeps each sign with its season by definition. The two zodiacs measure the same positions from different starting points; whether either means anything is a separate question.

  • Each Sun sign has fixed calendar dates, such as 21 March to 19 April for Aries.

    false

    Who says it: Newspaper horoscopes and most popular astrology sites.

    What the record shows: The Sun enters each sign at a different moment each year, and the date also depends on the time zone; in 2024 to 2028 Aries began on 20 March at times from 02:17 to 20:24 UTC. The chart decides.

  • Studies show that birth charts describe personality.

    false

    Who says it: Chart sites and apps.

    What the record shows: The controlled tests found astrologers at chance.

  • Carlson's 1985 test proved astrology false; or, Ertel's 2009 reanalysis proved the astrologers right.

    disputed

    Who says it: Sceptics' summaries on one side; Suitbert Ertel and the astrologers who cite him on the other.

    What the record shows: Carlson's astrologers matched charts to profiles at chance. Ertel's reanalysis of the same data reports a marginal effect that he himself calls insufficient. One test settles nothing either way.

  • The Mars effect proves that the planets shape people.

    disputed

    Who says it: Michel Gauquelin and later writers.

    What the record shows: It was replicated on data Gauquelin had collected, not by the American and French tests; and it concerns the daily position of one planet, not signs, houses or aspects.

  • Placidus is the traditional, or the original, house system.

    false

    Who says it: Many chart sites and beginners' books, because it is the software default.

    What the record shows: The Hellenistic tradition used whole-sign houses. The Placidus division was first published by Magini in 1602; it is the most used today, not the oldest.

  • There is one correct house system, and a planet's house is a fact of the sky.

    disputed

    Who says it: Users of every system; apps that offer no choice.

    What the record shows: A planet's house depends on the division chosen: between Placidus and Whole Sign a median of twelve of sixteen objects changed house in our 56 test charts. We default to Placidus and show the system on the chart.

  • One set of orbs, such as 10° for every aspect, is the standard.

    disputed

    Who says it: Software defaults presented as rules.

    What the record shows: Orbs differ by school: Lilly gave each planet its own; astro.com's default is a flat 10°, 6° for the sextile; others scale by planet; CHANI counts by sign. Ours are printed with every chart.

  • Uranus, Neptune and Pluto rule Aquarius, Pisces and Scorpio.

    disputed

    Who says it: Modern Western astrology, from John Varley in 1828 to the rulership lists of 1936.

    What the record shows: A modern attribution made in stages after the three discoveries; the traditional rulers are Saturn, Jupiter and Mars, and the traditional revival keeps them. We name the traditional ruler first and the modern co-ruler beside it.

  • The Part of Fortune is always Ascendant plus Moon minus Sun.

    disputed

    Who says it: Ptolemy, Lilly (1647), much 20th-century software and many sites.

    What the record shows: Valens and Dorotheus reversed the formula for night births, and astro.com does by default. Both are conventions; we reverse at night and name the formula used.

  • Lilith is a dark second moon of the Earth, a body in the chart.

    false

    Who says it: Sepharial (1918), after a claim of 1898; sites that merge the three Liliths.

    What the record shows: Three things carry the name: a second moon claimed in 1898 and never confirmed, the asteroid 1181 Lilith, and the Moon's apogee, an empty point. We show the mean apogee.

  • The Vertex is the point of fate, marking fated meetings.

    unverified

    Who says it: Charles Jayne's school and the many sites that follow it.

    What the record shows: The Vertex is a point of the twentieth century; Jayne and Johndro read it as matters beyond one's control. The reading has no older tradition, and nothing shows that it describes anyone.

  • Chiron, the wounded healer, is an ancient part of astrology.

    false

    Who says it: Sites that list Chiron beside the planets without a date.

    What the record shows: Chiron was announced on 1 November 1977, and astrologers took it up in the 1980s. The reading comes from the Greek myth of the centaur.

  • The chart is cast for the exact millisecond of birth.

    false

    Who says it: Our own old page, before 2026-10-11, and many chart sites.

    What the record shows: Birth times are recorded to the minute at best, and the engine takes minutes. The Ascendant moves about a degree every four minutes; a millisecond means nothing here.

  • A chart cast for noon, without a birth time, still gives the right Moon sign and houses.

    false

    Who says it: Sites that quietly cast at noon.

    What the record shows: At noon the Moon can be up to about 7° from its true place, enough to change its sign for about one birth in four, and the Ascendant and houses are unknown. Our chart marks a noon chart.

  • The chart foretells illness, accidents, money and the outcome of lawsuits.

    unverified

    Who says it: The traditional texts, from the Tetrabiblos to Lilly, and many sites and readings.

    What the record shows: The tradition makes such claims; we never do. Our pages and readings describe themes and tendencies, never outcomes.

Stories and lore

  • The hour-marker. The Greek horoskopos, "hour-marker", named the degree rising in the east at birth, the point that ties a sky to a place and a time and starts the twelve places; the chart and the word "horoscope" take their names from it. The tradition told that the art was given to the pharaoh Nechepso and his priest Petosiris, and to Hermes Trismegistus; Firmicus Maternus repeats the story in the 4th century, and the names belong to textbooks written in the 2nd and 1st centuries BCE.
  • The decans. The thirty-six Egyptian decans were star groups whose risings marked the hours of the night. The Hellenistic chart cut each sign into three decans of 10°, and our chart still names a body's decan.
  • Kepler's hen. Kepler compared the bulk of astrology's traditional rules to a dung heap in which a busy hen might still find a grain of corn, or a pearl. He cast more than 800 nativities all the same, one of them for Wallenstein.
  • Alan Leo in court. Leo was charged in 1914 with pretending to tell fortunes and the case was dismissed; charged again, he was convicted on 16 July 1917 and fined, though he argued that he described only tendencies. He died six weeks later. The shift he argued for, from events to tendencies, is the one our readings follow.
  • The princess and the airship. On 24 August 1930 the Sunday Express printed R. H. Naylor's horoscope for the newborn Princess Margaret. A line about danger to aircraft in October, followed by the R101 airship disaster on 5 October, won Naylor a weekly column, and the sun-sign column spread from there.
  • Jung's horoscopes. On 6 September 1947 Jung wrote to the Indian astrologer B. V. Raman that in difficult psychological diagnoses he usually had a horoscope cast for a further point of view, and that it often clarified what he could not otherwise understand.
  • The three Bobs. Project Hindsight began in 1993 when Robert Schmidt, Robert Hand and Robert Zoller set out to translate the Greek and Latin sources on a monthly subscription; whole-sign houses and sect came back into use from those translations.
  • The facsimile. Olivia Barclay found an original copy of Lilly's Christian Astrology in 1980 and had it reprinted in facsimile in 1985, which is where the traditional revival in Britain is usually said to begin.
  • Chiron's key. Chiron's glyph is a key, and also a K for Charles Kowal, who found it. The reading astrologers give it comes from the Greek centaur who taught healing and could not heal his own wound.

Evidence and criticism

The controlled tests. In Nature in December 1985 Shawn Carlson reported a double-blind test, its design agreed in advance with astrologers, in which they matched 116 natal charts to personality profiles; they scored at chance, and their confidence did not predict their success. Suitbert Ertel reanalysed the same data in 2009 and reported a marginal effect, which he himself called too small to show that astrology works but enough, in his view, to make Carlson's verdict untenable; he published it in the Journal of Scientific Exploration, outside the mainstream literature, and we found no new test that repeats it. Geoffrey Dean and Ivan Kelly (2003) reported tests of "time twins", people born minutes apart, who showed no shared traits, and tests in which astrologers did no better than people working without charts. A pooled analysis of 40 studies, with some 700 astrologers and more than 1,000 charts, found nothing once obvious cues were removed.

The Mars effect. Michel Gauquelin reported in 1955 that sports champions were born more often just after Mars rose or culminated. A Belgian committee replicated it in 1967 on data he had mostly collected; an American test (1979 to 1980) and a French one (published 1996, 209 of 1,120 champions against a base rate of about 17.7 percent) found no effect; critics proposed misreported birth times as a cause. Whatever its status, it concerns the daily position of one planet, not signs, houses or aspects.

Our own tests show that the positions match independent astronomy to under one arc second and that the houses, points and aspects follow the stated conventions.

The tradition's own debates are about conventions: the house system, the orbs, which node and which Lilith, the day and night Lot of Fortune, the modern rulers, and whether the psychological or the traditional reading is the true art. Reviews of chart apps ask most for explanation, fewer aspect lines and a choice of house system.

Older criticism. Pico della Mirandola argued in 1496 that the planets act on the Earth only through light and heat. Once Newtonian physics took away its rationale, astrology left the universities in the 18th century.

Terms

Natal chart, birth chart
The sky at the moment and place of a birth, drawn as a wheel. We avoid "horoscope" for it, since the word now usually means the newspaper column.
Tropical zodiac
Twelve equal signs of 30° counted from the March equinox, so each sign keeps its season. Western astrology uses it; Jyotisha counts from the stars instead.
Sign
One twelfth of the ecliptic, named after a nearby constellation but not the same thing as it. Elements fire, earth, air and water; modalities cardinal, fixed and mutable.
Planets, luminaries
"The planets" in the tradition's usage are the Sun, the Moon and the planets proper; the Sun and Moon are the luminaries.
House, cusp
One of twelve divisions of the local sky, counted from the Ascendant; the cusp is its starting degree. How the sky is divided depends on the house system, which we name.
Ascendant, rising sign
The degree of the zodiac rising in the east at birth, in Greek the horoskopos or hour-marker; its sign is the rising sign. Opposite it is the Descendant.
Midheaven, IC
The Midheaven (MC) is the degree culminating on the meridian; the IC is opposite it. With the Ascendant and Descendant, the four angles.
Aspect, orb
An angle between two bodies close to 0°, 60°, 90°, 120°, 150° or 180°; the orb is how far from exact it may be and still count. Squares and oppositions are called hard, trines and sextiles soft, never bad and good.
Applying, separating
Whether two bodies are moving towards an exact aspect or away from it, judged from their speeds. Not given for the angles, which outrun every body.
Domicile, exaltation, detriment, fall
A planet's own sign, the sign where it is exalted, and the signs opposite each, where the tradition calls it weakened. The houses and exaltations are Ptolemy's; the word "detriment" is medieval.
Chart ruler
The traditional ruler of the rising sign, Lilly's lord of the Ascendant; we name the modern co-ruler beside it for Scorpio, Aquarius and Pisces.
Retrograde
A planet that seems, from the Earth, to move backwards through the zodiac for a while. We write the word out rather than use the symbol alone.
Lunar nodes
The two points where the Moon's path crosses the ecliptic, North (ascending) and South; the Dragon's Head and Tail of medieval astrology, Rahu and Ketu in Jyotisha.
Lilith (mean), Black Moon
In our chart, the mean apogee of the Moon's orbit: an empty point, never a "dark moon".
Part of Fortune, lot
A lot is a point counted from the Ascendant by the distance between two bodies; the Part of Fortune, or Lot of Fortune, measures from the Sun to the Moon.
Vertex
Where the prime vertical meets the ecliptic in the west: a twentieth-century point.
Decan
A third of a sign, 10°; originally one of the thirty-six Egyptian star groups that marked the hours of the night.
Out of bounds
A body whose declination is beyond the Sun's farthest, about 23.44°.
Day and night charts
A chart is a day chart when the Sun is above the horizon at the birth place; the Hellenistic doctrine of sect builds on it, and our Part of Fortune follows it.
Rudhyar's Moon phases
Eight 45° slices of the Sun-Moon angle, from New to Balsamic, as Dane Rudhyar named them in 1967; we call the slices from 0° to 45° and from 180° to 225° "New" and "Full".
Placidus, Whole Sign, Equal, Porphyry
Ways of dividing the houses: by time (Placidus), by whole signs from the rising sign, by 30° from the Ascendant, or by trisecting the quadrants (Porphyry, our fallback above the polar circles).

Sample reading

Sample reading, AI-written for a fictional person.

Read the sample (1,289 words)

AI output can be wrong.

The Warmth You Bring Into a Room Is Already Working

Jason, your chart rises at Leo 21°03', and its ruler, the Sun, sits at 29°55' Capricorn in the sixth house, in the very last minutes of the sign. Opposite your chart's horizon, the Moon at 7°47' Cancer in the eleventh house faces Saturn at 7°47' Capricorn in the fifth across an orb of 0.0°. This is a night chart, and in Rudhyar's scheme the Moon was in its Gibbous phase.

Astrologers read the Leo Ascendant as the manner of arrival: warmth, presence, a face turned toward others as though light should be shared. Yet the lord of that Ascendant does not live in Leo's theatre. It sits in Capricorn, Saturn's sign, in the house the tradition gives to work, service and daily routine. The glow people see is real, and it is also on duty. You enter a room generous and bright. Within ten minutes you know who needs a chair, which plan has a hole in it, and what you will be doing about it tomorrow.

The Sun at the final degree of Capricorn carries the sign's whole climb to its end. The tradition reads Capricorn as patience, structure and the thing built to last. At its last degree that quality is complete and slightly weary, as if you were born already knowing how long things take. The Sun's trine to Jupiter at 26°05' Taurus in the tenth, retrograde, orb 3.8°, gives that labour an ease the tradition counts as support. Steadiness in you reads to others as trustworthiness, and Jupiter's backward motion turns the reward inward: the sense of having done right matters more to you than being seen doing it.

Feeling and Its Custodian, Face to Face

The opposition between your Moon and Saturn is the hinge of this chart. Both bodies are in their own signs. The Moon rules Cancer and Saturn rules Capricorn, so neither yields. The tradition reads Cancer as the need to belong and be held. It reads Capricorn as the discipline that decides what is safe to show. In your chart they sit at the same degree on opposite sides of the circle, with no gap at all.

In practice your feelings arrive with a supervisor attached. A friend asks how you really are. Something true rises, and almost in the same breath a second voice asks whether it is appropriate, whether it is too much, whether you have earned the right to need it. The answer that comes out is honest but edited. People come away feeling cared for and slightly unsure they ever met the person underneath.

The Moon in the eleventh house sets these needs among friends, groups and shared hopes. You are often the one who keeps a circle together: you remember birthdays and quietly absorb the mood of the group. The Moon's trine to the North Node, and its looser trine to Pluto at 14°57' Scorpio in the fourth, orb 7.2°, give these instincts depth and a pull toward partnership. Both are easier currents. The North Node is a modern point, read here as the tradition's sense of growth through open, porous connection with another person. Its opposite, the South Node, is the familiar habit of meeting life by sorting, correcting and being useful.

Chiron at 2°41' Cancer in the eleventh, retrograde, sits beside your Moon and opposes Uranus at 2°51' Capricorn by 0.2°. Chiron is a modern addition, and astrologers read it as a sore place that becomes a teaching. Here it sits squarely in belonging. It marks an old ache about fitting in that you learned to manage by becoming indispensable.

Where Pleasure Has to Earn Its Keep

Your fifth house, the house of pleasure, play, romance and creation, holds four bodies in Capricorn: Venus at 11°35', Saturn at 7°47', Uranus at 2°51' and Neptune at 10°37'. The Vertex at 11°06' Capricorn sits among them too. The Uranus and Neptune conjunction is shared by everyone born in those years. What is yours alone is that it lands in this house, wrapped around Venus and Saturn, and that all four oppose your Moon.

The tradition reads Saturn in its own sign as strong and serious. In the fifth house it means joy is treated as a responsibility. You finish something you made, a meal, a drawing, a plan for a weekend, and your first move is to check it for flaws. Fun needs a structure before you trust it. Venus conjunct Neptune at 1.0° softens this considerably. Your taste is refined and atmospheric, drawn to the beautiful thing that cannot quite be pinned down, and you love in a way that idealises. Venus conjunct Saturn at 3.8° asks that love prove itself over time. You are slow to declare and steadfast once you have.

Uranus in the same cluster adds a wilful streak. Just when your pleasures have become reliable, something in you wants to break the form. Venus and Neptune both trine the Midheaven. That gives your public face a grace that comes from this same fifth house. What you make with care tends to become what you are known for.

The cost: every one of these bodies opposes the Moon. Your most private needs and your most deliberate pleasures sit at opposite ends of the chart. Feeling safe and feeling delighted rarely happen in the same hour. You can be very good at creating beauty for others while your own appetite for comfort waits outside the door.

The Mind That Argues With the Mountain

Mars at 0°22' Taurus in the ninth house squares your Sun with an orb of 0.5°, the tightest aspect in the chart. The tradition reads the square as friction and effort. Here the drive in you and the beliefs that move you are set at an angle. Mars has just entered Taurus, fixed and stubborn, in the house of belief and wider horizons. When you are sure of something, you plant your feet. Your Capricorn Sun would rather proceed by strategy and patience. The friction produces stamina. It also produces moments when you dig in over a principle long past the point where it serves you, then resent the extra weight you have taken on. Mars trines Uranus by 2.5° and Saturn by 7.4°, so the energy has outlets: you work best when the stubbornness has a structure to push against.

Mercury at 10°23' Aquarius in the sixth, retrograde, squares the Midheaven and squares Pluto by 4.6°. Your thinking is independent, reflective and slow to commit, because it turns ideas over several times before speaking. The square to Pluto in the fourth, the house of origins, gives that thought an investigative edge, a need to get to the bottom of things, especially family patterns. Pluto opposes the Midheaven. That intensity at home runs straight up the chart's vertical axis to your public face. What you show the world is calm Taurus. What fuels it is Scorpio, underground and unsentimental.

The trap in all of this is plain. With the chart ruler in the sixth house, Saturn in its own sign, and the Moon's needs supervised at 0.0°, you can turn your entire inner life into a list of duties. The Leo rising promises a warmth that the rest of the chart keeps sending to work. People may experience you as reliable and gracious and never guess you are tired or hungry for play.

Something practical: once a week, set aside an hour for something purely of the fifth house, play with no product, and do not judge it, correct it or tell anyone about it. Before that hour starts, say one unedited sentence about how you feel to someone in your circle. Treat the Saturn in you as the one who guards the time, not the one who grades it.

Get the reading · $3.99 for Natal Chart

Related systems

Sources

Primary texts (21)
  1. NASA Jet Propulsion Laboratory, JPL Horizons system (planets DE441; Chiron orbit solution JPL#171). 2026. ssd.jpl.nasa.gov/api/horizons.api
  2. Claudius Ptolemy; tr. Frank Egleston Robbins, Ptolemy, Tetrabiblos, translated by F. E. Robbins (Loeb Classical Library, 1940), online at LacusCurtius. Harvard University Press; penelope.uchicago.edu, 1940. Public domain in the United States only; used for facts and chapter numbers. penelope.uchicago.edu/Thayer/E/Roman/Texts/Ptolemy/Tetrabiblos/home.html
  3. Claudius Ptolemy; tr. J. M. Ashmand, Ptolemy's Tetrabiblos, or Quadripartite: being four books of the influence of the stars, translated by J. M. Ashmand (from the paraphrase of Proclus). Davis and Dickson, London, 1822. Public domain; quoted briefly. archive.org/details/b29293066
  4. Vettius Valens; tr. Mark T. Riley, Vettius Valens, Anthologies, translated by Mark T. Riley (preliminary translation, released 2010). Skyscript (hosting the author's PDF), 2010. The translator's copyright; facts and chapter references only. skyscript.co.uk/valens_riley.html
  5. Dorotheus of Sidon; ed. David Pingree (1976); tr. Benjamin N. Dykes (2017), Dorotheus of Sidon, Carmen Astrologicum (Pingree's 1976 Teubner edition of the Arabic version with Greek and Latin fragments; Dykes' 2017 translation of 'Umar al-Tabari's Arabic, Cazimi Press). Teubner, Leipzig; Cazimi Press, Minneapolis, 1976. In copyright; facts and chapter references only. cambridge.org/core/journals/classical-review/article/pingreedavid-dorothei-sidonii-carmen-astrologicum-pp-xx-444-leipzig-teubner-1976-cloth/2AAE046FFCF84AFF7B3C2F752F55BCFA
  6. Julius Firmicus Maternus; tr. James H. Holden, Julius Firmicus Maternus, Mathesis, translated by James H. Holden. American Federation of Astrologers, Tempe, 2011. In copyright; facts and chapter references only.
  7. Abu Ma'shar; ed. and tr. Keiji Yamamoto, Charles Burnett, The Great Introduction to Astrology by Abu Ma'shar, edited and translated by Keiji Yamamoto and Charles Burnett, with an edition of the Greek version by David Pingree. Brill, Leiden, 2019. In copyright; facts and chapter references only. doi.org/10.1163/9789004381230
  8. Guido Bonatti; tr. Benjamin N. Dykes, Guido Bonatti, Book of Astronomy (Liber Astronomiae), translated by Benjamin N. Dykes. Cazimi Press, Golden Valley, Minnesota, 2007. In copyright; facts and chapter references only. lccn.loc.gov/2007928010
  9. William Lilly, Christian Astrology, modestly treated of in three books. Thomas Brudenell for John Partridge and Humphrey Blunden, London, 1647. Public domain; quoted briefly, from the 1647 edition. archive.org/details/b30338724
  10. Johannes Kepler, Harmonices mundi libri V. Linz, 1619. Public domain. en.wikipedia.org/wiki/Harmonice_Mundi
  11. C. G. Jung; ed. Gerhard Adler, Aniela Jaffe, C. G. Jung, Letters, Volume 1: 1906-1950 (letter to B. V. Raman, 6 September 1947). Princeton University Press, 1973. In copyright; facts only, the wording checked against a scan of the printed volume. press.princeton.edu/books/paperback/9780691098951/letters-of-c-g-jung
  12. C. G. Jung, Synchronicity: An Acausal Connecting Principle (Collected Works 8), with the astrological marriage experiment. Rascher, Zurich; Princeton University Press (CW 8, 1960), 1952. In copyright; facts only.
  13. Michel Gauquelin, L'influence des astres: etude critique et experimentale. Editions du Dauphin, Paris, 1955. Known through the works that test it.
  14. Positional Astronomy Centre, India Meteorological Department, Rashtriya Panchang 1948 Saka (2026-27), online edition: ayanamsa by month, daily nirayana longitudes of the Sun and Moon, explanation page. Government of India, Kolkata, 2026. packolkata.imd.gov.in/panchang/index.php/en
  15. Calendar Reform Committee (M. N. Saha, chairman; N. C. Lahiri, secretary), Report of the Calendar Reform Committee. Council of Scientific and Industrial Research, New Delhi, 1955. packolkata.imd.gov.in/history.php
  16. Alan Leo (William Frederick Allan), Astrology for All, to which is added a complete system of predictive astrology for advanced students. Modern Astrology Office, London, 1899. Public domain; quoted briefly. archive.org/details/bub_gb_8CwSAAAAYAAJ
  17. Hermetic Order of the Golden Dawn (S. L. MacGregor Mathers), Book T: The Tarot (the Golden Dawn tarot paper). privately circulated; archive.org item mathers-and-felkin-golden-dawn-book-t-the-tarot-1888, late 1880s or early 1890s. Public domain. archive.org/details/mathers-and-felkin-golden-dawn-book-t-the-tarot-1888
  18. Varahamihira; tr. N. Chidambaram Iyer, The Brihat Jataka of Varaha Mihira, translated by N. Chidambaram Iyer. Foster Press, Madras, 1885. Public domain. archive.org/details/b2488442x
  19. Abu'l-Rayhan Muhammad ibn Ahmad al-Biruni; tr. R. Ramsay Wright, The Book of Instruction in the Elements of the Art of Astrology, translated by R. Ramsay Wright. Luzac, London (written in Ghazna, 1029), 1934. In copyright; facts and section numbers only. lccn.loc.gov/35038118
  20. NASA, Constellations and the Calendar (NASA Tumblr, 20 September 2016), Wayback Machine copy of 23 September 2016. nasa.tumblr.com, 2016. A US government work, public domain. web.archive.org/web/20160923131919/http://nasa.tumblr.com/post/150688852794/zodiac
  21. Paul Foster Case, A Course on Tarot Divination (The Oracle of Tarot), lesson 1, figure 1-2 'Astrological Attributions of the Major Trumps'. School of Ageless Wisdom (mimeographed course); transcription by TarotWorks, hosted by benebellwen.com, 1933. Facts only. benebellwen.com/wp-content/uploads/2013/02/paul-foster-case-oracle-of-the-tarot-1933-source-credit-tarotworks.pdf
Studies and other sources (62)
  1. Astrodienst AG (Dieter Koch, Alois Treindl), Swiss Ephemeris programming interface and general documentation (sections 2.2 lunar nodes and apogees, 2.8 sidereal and ayanamsha, 6.3 to 6.4 Vertex and polar houses, Appendix E published ayanamsha values). Astrodienst, Zurich, 2022. Read as documentation only; facts only. astro.com/swisseph/swisseph.htm
  2. Astrodienst AG, Astrodienst (astro.com) chart defaults and FAQ pages: style defaults, aspects and orb tables, calculations (Part of Fortune), extra factors (Lilith), settings (orbs of points), house systems. Astrodienst, Zurich, 2026. Consulted for facts; never copied. astro.com/faq/fq_fh_calc_e.htm
  3. Astrodienst AG, Astrowiki: Orb. Astrodienst, Zurich, 2026. Consulted for facts; never copied. astro.com/astrowiki/en/Orb
  4. Astro-Seek, Astro-Seek birth chart form (defaults read, nothing submitted). 2026. Defaults read, nothing submitted; never copied. horoscopes.astro-seek.com/birth-chart-horoscope-online
  5. CHANI, CHANI: What whole sign houses are and why we use them; CHANI help: aspects used in the app. 2026. Consulted for facts; never copied. chani.com/astro-education/what-whole-sign-houses-are-and-why-we-use-them
  6. Co-Star Astrology Society, Co-Star: house systems. 2026. Consulted for facts; never copied. costarastrology.com/how-does-astrology-work/house-systems
  7. Brandon Rhodes, Skyfield: LICENSE (MIT). 2018. github.com/skyfielders/python-skyfield/blob/master/LICENSE
  8. Ryan S. Park, William M. Folkner, James G. Williams, Dale H. Boggs, The JPL Planetary and Lunar Ephemerides DE440 and DE441. The Astronomical Journal 161:105, 2021. doi.org/10.3847/1538-3881/abd414
  9. N. Capitaine, P. T. Wallace, J. Chapront, Expressions for IAU 2000 precession quantities. Astronomy and Astrophysics 412, 567-586, 2003. doi.org/10.1051/0004-6361:20031539
  10. Wikipedia contributors, Wikipedia: Axial precession. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Axial_precession
  11. Francesca Rochberg, Babylonian Horoscopes. American Philosophical Society, Philadelphia, 1998. sites.dlib.nyu.edu/viewer/books/isaw_aphs000011/1
  12. Francesca Rochberg, The Heavenly Writing: Divination, Horoscopy, and Astronomy in Mesopotamian Culture. Cambridge University Press, 2004. doi.org/10.1017/CBO9780511617409
  13. Abraham Sachs, Babylonian Horoscopes. Journal of Cuneiform Studies 6, 1952. doi.org/10.2307/1359035
  14. John P. Britton, Studies in Babylonian lunar theory: part III. The introduction of the uniform zodiac. Archive for History of Exact Sciences 64, 2010. doi.org/10.1007/s00407-010-0064-z
  15. Wikipedia contributors, Wikipedia: Zodiac. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Zodiac
  16. Wikipedia contributors, Wikipedia: Enuma Anu Enlil. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Enuma_Anu_Enlil
  17. Wikipedia contributors, Wikipedia: Hellenistic astrology. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Hellenistic_astrology
  18. Wikipedia contributors, Wikipedia: History of astrology. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/History_of_astrology
  19. Wikipedia contributors, Wikipedia: Johannes Kepler (section on astrology). 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Johannes_Kepler
  20. Wikipedia contributors, Wikipedia: Astrological aspect. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Astrological_aspect
  21. Wikipedia contributors, Wikipedia: House (astrology). 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/House_(astrology)
  22. Wikipedia contributors, Wikipedia: Walter Koch (astrologer). 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Walter_Koch_(astrologer)
  23. Wikipedia contributors, Wikipedia: Alan Leo. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Alan_Leo
  24. Wikipedia contributors, Wikipedia: R. H. Naylor. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/R._H._Naylor
  25. Wikipedia contributors, Wikipedia: Dane Rudhyar. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Dane_Rudhyar
  26. Dane Rudhyar, The Lunation Cycle: A Key to the Understanding of Personality. Servire, The Hague; Aurora Press, Santa Fe, 1967. In copyright; facts only.
  27. Wikipedia contributors, Wikipedia: Liz Greene. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Liz_Greene
  28. Chris Brennan, The Astrology Podcast: Early Project Hindsight interview with Hand, Schmidt and Zoller; Ep. 417 commentary. The Astrology Podcast, 2023. Consulted for facts. theastrologypodcast.com/2023/09/03/early-project-hindsight-interview-with-hand-schmidt-and-zoller
  29. Chris Brennan, Hellenistic Astrology: The Study of Fate and Fortune. Amor Fati Publications, Denver, 2017. In copyright; facts only.
  30. Wikipedia contributors, Wikipedia: Olivia Barclay. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Olivia_Barclay
  31. Wikipedia contributors, Wikipedia: 2060 Chiron. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/2060_Chiron
  32. Chris Brennan, Melanie Reinhart, The Astrology Podcast, Ep. 271: The Astrology of Chiron, with Melanie Reinhart. The Astrology Podcast, 2020. Consulted for facts. theastrologypodcast.com/2020/09/16/the-astrology-of-chiron-with-melanie-reinhart
  33. Wikipedia contributors, Wikipedia: Lilith (hypothetical moon). 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Lilith_(hypothetical_moon)
  34. Wikipedia contributors, Wikipedia: 1181 Lilith. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/1181_Lilith
  35. Wikipedia contributors, Wikipedia: Don Neroman. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Don_Neroman
  36. Bill Meridian (Urania Trust), Lorne Edward Johndro (Urania Trust, celebrated astrologers). 2016. Consulted for facts. uraniatrust.org/celebrated-astrologers/edward-johndro
  37. Wikipedia contributors, Wikipedia: Astrology and science. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Astrology_and_science
  38. Shawn Carlson, A double-blind test of astrology. Nature 318, 1985. Read at abstract level. doi.org/10.1038/318419a0
  39. Suitbert Ertel, Appraisal of Shawn Carlson's Renowned Astrology Tests. Journal of Scientific Exploration 23, 2009. Read in the journal's open PDF. journalofscientificexploration.org/index.php/jse/article/view/99
  40. Geoffrey Dean, Ivan W. Kelly, Is Astrology Relevant to Consciousness and Psi?. Journal of Consciousness Studies 10, 2003. Read at abstract level. ingentaconnect.com/content/imp/jcs/2003/00000010/f0020006/art00010
  41. Wikipedia contributors, Wikipedia: Mars effect. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Mars_effect
  42. Claude Benski and others, The 'Mars Effect': A French Test of Over 1,000 Sports Champions. Prometheus Books, Amherst, New York, 1996. Known through the works that cite it.
  43. Wikipedia contributors, Wikipedia: Ophiuchus (astrology). 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Ophiuchus_(astrology)
  44. Wikipedia contributors, Wikipedia: Sidereal and tropical astrology. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Sidereal_and_tropical_astrology
  45. Wikipedia contributors, Wikipedia: Ayanamsa. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Ayanamsa
  46. Wikipedia contributors, Wikipedia: Cyril Fagan. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Cyril_Fagan
  47. Chris Brennan, Kenneth Bowser, The Astrology Podcast, Ep. 122: Western Sidereal Astrology, with Kenneth Bowser. The Astrology Podcast, 2017. theastrologypodcast.com/2017/07/24/western-sidereal-astrology-with-kenneth-bowser
  48. Wikipedia contributors, Wikipedia: Indian national calendar. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Indian_national_calendar
  49. Wikipedia contributors, Wikipedia: Hindu astrology. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Hindu_astrology
  50. Bill M. Mak, The Date and Nature of Sphujidhvaja's Yavanajataka Reconsidered in the Light of Some Newly Discovered Materials. History of Science in South Asia 1, 2013. doi.org/10.18732/H2RP4T
  51. Wikipedia contributors, Wikipedia: Yavanajataka. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Yavanajataka
  52. Drik Panchang, Drik Panchang: Kundali (birth chart) page and its options. 2026. Consulted for facts; never copied. drikpanchang.com/jyotisha/kundali/kundali.html
  53. P. V. R. Narasimha Rao, Jagannatha Hora: features. 2026. Consulted for facts; never copied. vedicastrologer.org/jh/features.htm
  54. NASA Goddard Space Flight Center, National Space Science Data Center (D. R. Williams), Planetary Fact Sheet (metric). NASA NSSDC, 2024. nssdc.gsfc.nasa.gov/planetary/factsheet
  55. NASA Jet Propulsion Laboratory, Solar System Dynamics, JPL Small-Body Database: 2060 Chiron (1977 UB). NASA JPL, 2026. ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2060
  56. Wikipedia contributors, Wikipedia: Uranus; Neptune; Pluto; Lunar node. Wikimedia Foundation, 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Lunar_node
  57. Wikipedia contributors, Wikipedia: Domicile (astrology); Exaltation (astrology); Essential dignity; Astrological sign. Wikimedia Foundation, 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Exaltation_(astrology)
  58. Bill Meridian (Urania Trust), Charles A. Jayne (Urania Trust, celebrated astrologers). Urania Trust, London, 2016. Consulted for facts. uraniatrust.org/celebrated-astrologers/charles-jayne
  59. Dom Neroman (1884 to 1953); College astrologique de France, Les presages a la lumiere des lois de l'evolution (BnF catalogue record cb31254351k). Editions 'Sous le ciel', Paris, 1937. catalogue.bnf.fr/ark:/12148/cb31254351k
  60. La langue francaise (online dictionary), Lune noire (definition and etymology). 2026. lalanguefrancaise.com/dictionnaire/definition/lune-noire
  61. Jan Willem Nienhuys, The Mars Effect in Retrospect. Skeptical Inquirer 21(6); online at skepsis.nl, 1997. skepsis.nl/mars-effect
  62. Wikipedia contributors, Wikipedia: Decan. 2026. CC BY-SA; consulted for facts. en.wikipedia.org/wiki/Decan
Our own research (9)
  1. EsoTerrier, Natal and sidereal wheels: research for the rebuild (README, report-main.md, notes/). Research folder 2026-10-11-natal-sidereal, 2026.
  2. EsoTerrier, Helper report: validation of the natal chart engine (tropical and sidereal). Validation report, 2026-10-11, 2026.
  3. EsoTerrier, Helper report: visual survey of natal and Jyotisha chart tools. Visual survey of chart tools, 2026-10-11, 2026.
  4. EsoTerrier, EsoTerrier chart engine: services/chart/ephemeris.py, calculation.py, jyotish.py, texts.py. python/esoterrier, services/chart, 2026.
  5. EsoTerrier, Calculation documentation: chart.md and chart_sidereal.md. Calculation documentation and sample data, 2026.
  6. EsoTerrier, Sun ingress dates 2024 to 2028 computed with Skyfield and JPL DE440s (notes/ingress-dates.json). Computed with Skyfield and JPL DE440s, 2026.
  7. EsoTerrier, Draconic chart and Sabian symbols research, 2026-10-10: the true against mean node simulation (notes/true-vs-mean-node-simulation.json). Research folder 2026-10-10-draconic-sabian, 2026.
  8. EsoTerrier, EsoTerrier app: resources/js/support/natal.ts and components/Chart/NatalChartTropical.vue. The chart component in our app, 2026.
  9. EsoTerrier, Knowledge layer shared topics: _shared/zodiac and _shared/planets (accuracy pass, 2026-10-13). Knowledge layer, shared topics, 2026.
Draw your free chart: natal chart No email needed
Get the reading · $3.99 for Natal Chart Contents ↑

By EsoTerrier. Written with AI assistance from our research and checked against its sources; last revised 20 October 2026. How we write these pages.

First published ; last revised . Corrections: support@esoterrier.com.