A vast brass armillary sphere ringed with zodiac figures hangs in a roofless Gothic hall at night, a cloaked figure below

As above

Astrology

A symbolic cosmology relating celestial order to earthly life.

The armillary is not a picture of the sky but a model of it — rings for the ecliptic, the equator, the meridian. To read a chart is to hold that machine in mind and ask where a body stood inside it.

Orientation

Reading Astrology

A man with a rolled chart under his arm climbs a spiral stair inside a stone tower, instruments in its niches, sky open far above

The Observatory Stair

Before the telescope, an observatory was a stair and a sightline: armillaries, quadrants, and rules kept in niches, and a long climb toward the open circle of sky. The astrology in this archive is the working knowledge such towers were built around.

From Babylonian omen lists and the Hellenistic horoscope to the Indian, Arabic and Latin systems and the modern revival: astrology as its own sources describe it, with the archive's instruments for working it.

  1. Astrology is not one system but a family of them, descended from Mesopotamian omen-watching through a Hellenistic synthesis that gave the West its horoscope: ascendant, houses, aspects, and lots, assembled in Greco-Roman Egypt around the second century BCE.

  2. The family then divides. India received the Hellenistic material and grew Jyotisha around the sidereal zodiac and the lunar mansions; China built its astral science on different foundations — an equatorial frame of twenty-eight lodges rather than an ecliptic zodiac, and stems, branches and the five phases — until Buddhist translations carried the Hellenistic signs east from the late sixth century, and Hellenistic horoscopy with them in the Tang; the Arabic world systematized what Rome let slip and handed it back to Latin Europe, in a trickle from tenth-century Catalonia and in full from the twelfth century.

  3. The page holds the working parts: the four branches of practice, the tropical and sidereal zodiacs, the glyphs, the house systems, and the chart shapes — with the atlas below drawing what prose describes, and the archive's own instruments linked where they compute it.

In brief

Four Branches

One sky, four questions: the same machinery answers each differently.

4 points
  • Natal — the birth moment
  • Horary — the question's moment
  • Electional — choosing a moment
  • Mundane — nations and epochs

Two Zodiacs

Tropical measures from the equinox; sidereal from the stars. On the Lahiri reckoning they coincided about 285 CE — other ayanamsas put the date between the third and fifth centuries — and they drift apart a degree every 72 years.

4 points
  • Tropical: seasons
  • Sidereal: constellations
  • Ayanamsa: the offset
  • Neither is 'wrong' — they measure different things

Aetherica Use

Where the archive's conversations work the art, chapter by chapter; the instruments are linked from the atlas above.

6 chapters
  • Priest-astronomers: omen, state and election before the horoscopeMagi and the Pre-Socratics 14:11
  • The Thema Mundi and the logic of the domicilesWind, Forms 0:49
  • The Chaldean order and the planets' housesWind, Forms 7:14
  • Sidereal for operations, tropical for nativities: one practitioner's ruleQabalistica Pt 2 29:35
  • An ill-dignified Mercury in the natal chartQabalistica Pt 2 31:25
  • Theurgic astrology: the chart as a working mapNeoplatonism 58:44

The Atlas

The working parts of a chart

Seven instruments of literacy: the glyphs a chart is written in, the arithmetic of the twelve signs, the houses and their meanings, the systems that argue over where their cusps fall, the aspects that let planets see one another, the shapes a whole chart makes at a glance, and the correspondence spine with the essential dignities. The seven house wheels are one chart, cast for latitude 45° north, so that their differences are real ones; the other wheels are schematic. Each doctrine is credited to the author who states it, because the tradition is many authors, not one rulebook. For real computation, the archive's instruments are linked at the end.

Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.12–24 Boll–Boer (= I.11–24 Robbins, Loeb)

The glyphs

Seven classical planets, three moderns, the lunar nodes, and the twelve signs — the complete alphabet of a chart.

  • SunThe luminary of day; vitality, sovereignty, the visible self
  • MoonThe luminary of night; body, memory, the daily life
  • MercurySpeech, exchange, craft — the go-between
  • VenusConcord, beauty, desire — the lesser benefic
  • MarsSeverance, courage, heat — the lesser malefic
  • JupiterIncrease, counsel, law — the greater benefic
  • SaturnLimit, time, structure — the greater malefic
  • UranusModern: rupture and invention (1781)
  • NeptuneModern: dissolution and glamour (1846)
  • PlutoModern: the underworld register (1930)
  • North NodeThe Moon's ascending crossing; increase, appetite
  • South NodeThe descending crossing; release, depletion
  • AriesCardinal fireruled by Mars
  • TaurusFixed earthruled by Venus
  • GeminiMutable airruled by Mercury
  • CancerCardinal waterruled by Moon
  • LeoFixed fireruled by Sun
  • VirgoMutable earthruled by Mercury
  • LibraCardinal airruled by Venus
  • ScorpioFixed waterruled by Mars
  • SagittariusMutable fireruled by Jupiter
  • CapricornCardinal earthruled by Saturn
  • AquariusFixed airruled by Saturn
  • PiscesMutable waterruled by Jupiter

Four elements × three modes

Four elements crossed with three modes give the twelve signs, and modern teaching reads most sign keywords off that grid. The grid is real; the reduction is recent. Ptolemy's three qualities are named from the seasons — tropical and equinoctial signs where a season turns, solid signs where it holds, bicorporeal signs where it hands over — and his triplicities carry planetary rulers and winds, not elements. Sign natures also come from gender, rulers and the figures themselves.

  • Fire vital spark, spirit, initiative

    Cardinal
    Aries
    Fixed
    Leo
    Mutable
    Sagittarius

  • Earth substance, sense, endurance

    Cardinal
    Capricorn
    Fixed
    Taurus
    Mutable
    Virgo

  • Air relation, speech, exchange

    Cardinal
    Libra
    Fixed
    Aquarius
    Mutable
    Gemini

  • Water feeling, memory, dissolution

    Cardinal
    Cancer
    Fixed
    Scorpio
    Mutable
    Pisces
Ptolemy’s qualities and the triplicitiesTetrabiblos I.12 and I.19 (Boll–Boer): the signs' seasonal qualities, and the rulers and winds of the four triplicities.

Ptolemy’s three qualities · Tetrabiblos I.12

  • τροπικά · ἰσημερινά (tropika · isēmerina) — tropical and equinoctial (the modern 'cardinal'): Aries, Cancer, Libra, Capricorn
  • στερεά (sterea) — solid (the modern 'fixed'): Taurus, Leo, Scorpio, Aquarius
  • δίσωμα (disōma) — bicorporeal (the modern 'mutable'): Gemini, Virgo, Sagittarius, Pisces

Ptolemy, Tetrabiblos (Apotelesmatika), I.12 Boll–Boer (= I.11 Robbins, Loeb)

The triplicities

Ptolemy's first triangle (Aries, Leo, Sagittarius) is ruled by the Sun by day and Jupiter by night and is 'northern' with a mixture of south-west wind; he names no element. The fire–earth–air–water assignment is standard in later authors.

Ptolemy, Tetrabiblos (Apotelesmatika), I.19 Boll–Boer (= I.18 Robbins, Loeb)

The twelve houses

Signs describe how; houses say where — twelve departments of a life, counted counterclockwise from the ascendant. The shaded quarters are the angular houses, where the chart touches its own frame and planets act at full strength; each gold glyph sits in the house where tradition says that planet rejoices — the doctrine of the joys, which goes hand in hand with the houses' oldest Greek names.

Vettius Valens, Anthology, II.15 (Kroll), 'Names of the places' — God (θεός) signifies the father, Goddess (θεά) the mother, Good Daimon children, Good Fortune marriage, Bad Daimon sufferings, Bad Fortune injuries. Valens gives the names, not the numbers of the places or the joys.

C. Brennan, Hellenistic Astrology: The Study of Fate and Fortune, Amor Fati, 2017, the chapter on the planetary joys

Angular · shaded — succedent follow — cadent fall away.Joys: ☿︎ I · ☽︎ III · ♀︎ V · ♂︎ VI · ☉︎ IX · ♃︎ XI · ♄︎ XII

  • IVitaLife

    angular · joy of ☿︎ Mercury

  • IILucrumGain

    succedent

  • IIIFratresBrothers

    cadent · joy of ☽︎ Moon

    θεά (thea) ‘the Goddess’

  • IVGenitorThe Parent

    angular

  • VNatiChildren

    succedent · joy of ♀︎︎ Venus

    ἀγαθὴ τύχη (agathē tychē) ‘Good Fortune’

  • VIValetudoHealth

    cadent · joy of ♂︎︎ Mars

    κακὴ τύχη (kakē tychē) ‘Bad Fortune’

  • VIIUxorThe Spouse

    angular

  • VIIIMorsDeath

    succedent

  • IXPietasPiety

    cadent · joy of ☉︎ Sun

    θεός (theos) ‘God’

  • XRegnumThe Kingdom

    angular

  • XIBenefactaGood Deeds

    succedent · joy of ♃︎ Jupiter

    ἀγαθὸς δαίμων (agathos daimōn) ‘Good Spirit’

  • XIICarcerThe Prison

    cadent · joy of ♄︎ Saturn

    κακὸς δαίμων (kakos daimōn) ‘Bad Spirit’

What each house governs
I
The helm: body, temperament, appearance — the self that arrives before anything happens to it.
II
Possessions and livelihood: what the life holds onto, and what holds it up.
III
Siblings, neighbours, short roads, letters — the daily circuit of the known.
IV
Parents, home, land and the grave: foundations at the bottom of the sky, where things begin and are buried.
V
Children, pleasure, art, play — what the life makes because it delights to.
VI
Illness, labour, service, and the beasts that work: the body's frictions and the work done under another's direction.
VII
Marriage and partnership — and the open rival: everyone met exactly at eye level.
VIII
Death, inheritance, and other people's goods: what crosses into the life from beyond its control.
IX
Religion, divination, long journeys and higher learning — everything sought far from home ('Iter', the journey, in other lists).
X
Honours, authority, the public summit: the visible top of the chart and of the life.
XI
Allies, patrons, friendship, hope — help that arrives because it was earned or loved into being.
XII
Confinement, exile, hidden enemies, self-undoing — and the retreats where all of that is faced.

Sources Medieval Latin mnemonic hexameter for the twelve houses, 'Vita, lucrum, fratres, genitor, nati, valetudo, / uxor, mors, pietas, regnum, benefactaque, carcer'

Seven ways to cut the circle

Houses assign the sky’s twelve departments of life. Systems differ on what exactly is divided — signs, the ecliptic, time, or space — and charts move house when the system changes. All seven wheels are one chart, cast for latitude 45° north (ascendant 25°46′ Libra, midheaven 1°45′ Leo), so the differences are real ones. The bright lines mark the angles where quadrant systems pin their frame; the dashed line is the midheaven where it falls off the tenth cusp.

  • Whole sign

    divides signs themselves

    How it divides

    The rising sign is the first house entire, and every sign is one house; the ascendant degree falls somewhere inside the first, and the midheaven usually in the ninth, tenth or eleventh sign. The main system of the Hellenistic and Indian traditions, revived widely since the 1990s.

    Sources Vettius Valens, Anthology, II.15 (Kroll), 'Names of the places'D. Houlding, Skyscript glossary of astrological terms, s.vv. 'Porphyry', 'Quadrant systems', 'Whole sign houses'

  • Equal

    divides the ecliptic, from the ASC

    How it divides

    Twelve equal houses measured from the ascendant degree, which is the first cusp. The midheaven floats free of the tenth cusp (dashed).

    Sources D. Houlding, Skyscript glossary of astrological terms, s.vv. 'Porphyry', 'Quadrant systems', 'Whole sign houses'

  • Porphyry

    divides each quadrant in thirds

    How it divides

    The simplest quadrant system: each quarter between the angles is cut into three equal parts. Named for Porphyry's Introduction (3rd century), but already in Vettius Valens (2nd century), who uses the trisection to judge a planet's strength rather than to assign its topics.

    Sources Vettius Valens, Anthology, III.2 (Kroll)D. Houlding, Skyscript glossary of astrological terms, s.vv. 'Porphyry', 'Quadrant systems', 'Whole sign houses'

  • Placidus

    divides diurnal time-arcs

    How it divides

    Divides the time a degree takes to pass between horizon and meridian. Named for Placidus de Titis (1650s); the default of English ephemerides from the nineteenth century and of most software since. Fails at polar latitudes.

    Sources Placidus de Titis, Tabulae primi mobilis, Padua, 1657D. Houlding, Skyscript glossary of astrological terms, s.vv. 'Porphyry', 'Quadrant systems', 'Whole sign houses'

  • Koch

    divides ascension times of the birthplace

    How it divides

    Walter Koch's 'birthplace houses' (1971), a time-arc method computed from the birthplace's own horizon. Popular in German-speaking practice.

    Sources W. Koch and E. Schäck, Häusertabellen des Geburtsortes, 1971

  • Regiomontanus

    divides the celestial equator

    How it divides

    Divides the celestial equator equally and projects to the ecliptic. Named for Regiomontanus' Tabulae directionum (written 1467), though the method is older; the system of Lilly and classical horary.

    Sources J. D. North, Horoscopes and History, London, 1986, chs. 2–3W. Lilly, Christian Astrology, London, 1647, Book I, the table of essential dignities

  • Campanus

    divides the prime vertical

    How it divides

    Divides the prime vertical — the great circle through east point, zenith and west point — into equal lunes. Named for Campanus of Novara (13th century).

    Sources J. D. North, Horoscopes and History, London, 1986, chs. 2–3

Seven small wheels showing how each house system divides the same chart, cast for latitude 45° north; in the whole-sign wheel the ascendant falls inside the first house, in the equal wheel the first cusp sits on the ascendant while a dashed midheaven line falls just off the tenth cusp, and the five quadrant wheels share their angles but cut the quarters between them differently. Cusps computed after the Swiss Ephemeris house formulas for latitude 45° N, RAMC 124°, obliquity 23.44°.

The grammar of aspect

Aspects are how planets see one another. Ptolemy names four configurations — opposition, trine, square, sextile — and justifies them by the consonant ratios of music; trines and sextiles join signs of one gender and are 'harmonious', squares and oppositions are not. The conjunction is counted with them by later authors. Signs one apart or five apart he calls disjunct: they are 'turned away from one another', the relation modern charts draw as the semisextile and the quincunx. An orb is the allowance either side of exactness, a later refinement of a doctrine first counted sign to sign; a planet moving toward perfection of an aspect is applying, and its promise is still ahead — moving away, it is separating, and the matter is already done.

Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.14 Boll–Boer (= I.13 Robbins, Loeb)Ptolemy, Tetrabiblos (Apotelesmatika), I.17 Boll–Boer (= I.16 Robbins, Loeb)Ptolemy, Tetrabiblos (Apotelesmatika), I.24 Boll–Boer (= I.24 Robbins, Loeb)

  • Conjunction

    0° · the circle undivided

    not a Ptolemaic configuration · orb ~8–10° (modern)

    Reading and sources

    Two planets fused into one working function. Neither easy nor hard in itself — its temper is entirely the temper of the planets joined. Ptolemy does not count it among his four configurations.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.14 Boll–Boer (= I.13 Robbins, Loeb)

  • Semisextile

    30° · the circle ÷ 12

    disjunct in Ptolemy · orb ~2° (modern)

    ἀσύνδετα (asyndeta)

    Reading and sources

    Adjacent signs, sharing no element or mode. In Ptolemy they are disjunct, 'turned away from one another'; modern practice draws a mild, nagging unlikeness.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.17 Boll–Boer (= I.16 Robbins, Loeb)

  • Sextile

    60° · the circle ÷ 6

    Ptolemaic · orb ~4–6° (modern)

    ἑξάγωνον (hexagōnon)

    Reading and sources

    Fire with air, earth with water: signs of one gender, which Ptolemy calls harmonious. Opportunity rather than gift — ease that must be invited to act.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.14 Boll–Boer (= I.13 Robbins, Loeb)

  • Square

    90° · the circle ÷ 4

    Ptolemaic · orb ~7–8° (modern)

    Reading and sources

    Signs of the same mode, and of opposite gender, collide at cross-purposes; Ptolemy calls the square inharmonious. The productive crisis: friction that builds the strength it demands.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.14 Boll–Boer (= I.13 Robbins, Loeb)

  • Trine

    120° · the circle ÷ 3

    Ptolemaic · orb ~8° (modern)

    τρίγωνον (trigōnon)

    Reading and sources

    Same element, effortless current; harmonious in Ptolemy. The chart's given talents — and, undisturbed, its laziest places.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.14 Boll–Boer (= I.13 Robbins, Loeb)

  • Quincunx

    150° · the circle ÷ 12 × 5

    disjunct in Ptolemy · orb ~2–3° (modern)

    ἀσύνδετα (asyndeta)

    Reading and sources

    No shared element, mode or gender. Ptolemy's other disjunct relation, which 'divides the whole circle into unequal parts'; modern practice reads perpetual adjustment between things with no common language.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.17 Boll–Boer (= I.16 Robbins, Loeb)

  • Opposition

    180° · the circle halved

    Ptolemaic · orb ~8–10° (modern)

    διάμετρον (diametron)

    Reading and sources

    Full awareness across an axis: confrontation, projection, partnership. Inharmonious in Ptolemy. What the square forces, the opposition negotiates.

    Sources Ptolemy, Tetrabiblos (Apotelesmatika), I.14 Boll–Boer (= I.13 Robbins, Loeb)

The seven shapes of a chart

Before reading any single placement, Marc Edmund Jones taught reading the whole distribution at once. His seven patterns — published in The Guide to Horoscope Interpretation (1941) and built for the ten-body chart that Pluto's discovery in 1930 had completed — treat the gestalt of a nativity as its first sentence: where the planets gather, where they leave the wheel bare, and which single body, if any, the geometry appoints to lead. The shaded arc marks the occupied stretch; the pale dot marks that appointed planet, which for the bundle, bowl and locomotive is the planet at the clockwise edge of the group, the first to be carried up over the ascendant by the daily turn.

Sources M. E. Jones, The Guide to Horoscope Interpretation, Philadelphia, 1941, the seven 'temperament types'

  • Bundle

    keynote · Concentration

    The figure and its reading

    All ten planets within about 120° — the span of a trine.

    Everything the chart has is gathered into one department of the sky, and the life tends to match: a specialist temperament that digs one channel deep rather than many shallow, with limited patience for whatever falls outside it.

    leading planetThe leading planet — first of the group by clockwise rotation — sets the agenda the whole cluster serves. Two-thirds of the wheel is empty; what the bundle ignores is as diagnostic as what it holds.

  • Bowl

    keynote · Self-containment

    The figure and its reading

    All ten planets within one half of the wheel (~180°).

    A hemisphere occupied and a hemisphere bare: the life carries its own sources and feels the missing half as a question. Jones read the bowl as self-contained purpose — something held that must eventually be carried across to the empty side.

    leading planetThe leading planet, at the clockwise edge of the group, leads the whole formation and describes how the person advances into the empty hemisphere. The rim of the bowl — which houses it spans — shows where the holding happens.

  • Bucket

    keynote · Direction

    The figure and its reading

    Nine planets in one half; a single planet alone in the other.

    A bowl with an outlet. The isolated planet becomes the handle through which everything the other nine gather is poured, and the life organizes itself around that point of application — cause, craft, mission, or grievance.

    the handleEverything rides on the handle: its sign, house, and aspects govern the discharge of the whole chart. A handle conjunct the group's midpoint opposition is the pattern at its purest.

  • Locomotive

    keynote · Drive

    The figure and its reading

    Two-thirds of the wheel occupied (~240°); an empty trine.

    Jones' figure of executive momentum: the empty trine registers as a felt lack, and the chart mobilizes around solving it. Self-starting, problem-hungry, with power delivered unevenly — like a wheel driven from one point.

    the engineThe engine — the planet that leads the train clockwise into the empty trine — is the chart's driver and its point of greatest torque. The middle of the empty trine names the prize the drive is secretly aimed at.

  • Seesaw

    keynote · Negotiation

    The figure and its reading

    Two opposing groups, separated by two gaps of 60° or more.

    A life conducted between two camps: two sets of commitments that face each other across the wheel and refuse to merge. The temperament weighs, compares, alternates — capable of real perspective, and of permanent postponement.

    where to lookThe oppositions that bridge the two groups are the working axes of the chart. The heavier cluster is the home base; the lighter one is the counterweight the life keeps returning to pick up.

  • Splay

    keynote · Individuality

    The figure and its reading

    Three uneven clusters — a tripod, often braced by a grand trine.

    Energy spiking in three distinct departments with real gaps between: the tripod stands on its own arrangement and resists schedule, category, and other people's priorities. Jones read it as rugged, ineradicable individuality.

    where to lookRead the three legs as a standing structure: the midpoint of each cluster names a footing, and any grand trine linking them is the pattern's brace — self-sufficiency built into the geometry.

  • Splash

    keynote · Breadth

    The figure and its reading

    Planets distributed around the whole wheel; no gap much over 60°.

    The opposite of the bundle: interests sown across every quarter of the sky. At best a genuine universality — many rooms lived in comfortably; at worst the classic diffusion of a life spread one planet deep everywhere.

    where to lookWith no leading planet to appoint, look for any tight conjunction to act as a gathering point, and fall back on the balance of elements and modes to find where the scatter secretly leans.

Seven small wheels of ten dots each showing Jones's chart shapes; in the bundle, bowl and locomotive the highlighted dot is the planet at the clockwise edge of the group.

The boundaries are judgment calls, not measurements: real charts are often hybrids, and a near-miss — a bowl with one straggler, a locomotive missing its gap by a few degrees — is read as the nearest pattern with the deviation noted. Jones would say the deviation is where the interpretation starts.

The correspondence spine & essential dignities

The seven classical planets in Chaldean order, with the day, the metal, and the two greater essential dignities — domicile and exaltation — beside the two debilities opposite them, detriment and fall. In its domicile a planet rules the ground it stands on; in exaltation it is an honoured guest; in detriment, opposite its home, it works in a place built on contrary principles; in fall, opposite its exaltation, its dignity is inverted. Triplicity, term and face complete the five essential dignities of the tradition; Ptolemy states the reasons for the houses and the exaltations, and the medieval authors scored all five. The full tables live in the correspondence explorer.

The five essential dignitiesHouse, exaltation, triplicity, term and face, each with its Greek and its source.

  • house (domicile)οἶκοι (oikoi)

    Cancer and Leo go to the luminaries as the most northern signs, the rest in pairs outward by the order of the spheres: Mercury, never more than one sign from the Sun, takes Gemini and Virgo; Venus, never more than two, Taurus and Libra.

    Ptolemy, Tetrabiblos (Apotelesmatika), I.18 Boll–Boer (= I.17 Robbins, Loeb)

  • exaltationὕψωμα (hypsōma)

    The Sun exalted in Aries, where the days begin to lengthen, and depressed in Libra.

    Ptolemy, Tetrabiblos (Apotelesmatika), I.20 Boll–Boer (= I.19 Robbins, Loeb)

  • fall ('depression')ταπείνωμα (tapeinōma)

    Ptolemy's word for the sign opposite the exaltation.

    Ptolemy, Tetrabiblos (Apotelesmatika), I.20 Boll–Boer (= I.19 Robbins, Loeb)

  • detriment

    Not a Ptolemaic category; the scored debility belongs to the medieval Arabic and Latin systematisation.

    W. Lilly, Christian Astrology, London, 1647, Book I, the table of essential dignities

  • SaturnSaturday · Lead

    Domicile
    Capricorn · Aquarius
    Exaltation
    Libra
    Detriment
    Cancer · Leo
    Fall
    Aries

  • JupiterThursday · Tin

    Domicile
    Sagittarius · Pisces
    Exaltation
    Cancer
    Detriment
    Gemini · Virgo
    Fall
    Capricorn

  • MarsTuesday · Iron

    Domicile
    Aries · Scorpio
    Exaltation
    Capricorn
    Detriment
    Taurus · Libra
    Fall
    Cancer

  • SunSunday · Gold

    Domicile
    Leo
    Exaltation
    Aries
    Detriment
    Aquarius
    Fall
    Libra

  • VenusFriday · Copper

    Domicile
    Taurus · Libra
    Exaltation
    Pisces
    Detriment
    Aries · Scorpio
    Fall
    Virgo

  • MercuryWednesday · Quicksilver

    Domicile
    Gemini · Virgo
    Exaltation
    Virgo
    Detriment
    Sagittarius · Pisces
    Fall
    Pisces

  • MoonMonday · Silver

    Domicile
    Cancer
    Exaltation
    Taurus
    Detriment
    Capricorn
    Fall
    Scorpio

Work it, not just read it

Much of what is drawn above can be worked live with the archive's instruments:

Celestial InstrumentDecan CalculatorLunar MansionsPlanetary HoursZodiacal HoursElection PlannerMoon PhaseFixed StarsPlanetary Correspondences

Heard in the archive

4 more chapters in the archive
Round metal doors stacked up a stone shaft open to the sky, statues flanking each, a figure climbing the stair to the lowest

The Ladder of the Planets

Celsus, quoted by Origen, describes the Mithraic 'ladder of seven gates, and an eighth gate at its top': lead for Kronos, tin for Aphrodite, bronze for Zeus, iron for Hermes, a mixed alloy for Ares, silver for the Moon, gold for the Sun. Read from the top down, the gates give the planets in the order of the days of the week. The road of souls, Celsus says, runs through the planets to earth and from earth — in both directions.

Dossier

The Astrology dossier

A dossier on the oldest continuous science of correspondence: omen lore to horoscopy, the great systems east and west, and the instruments this archive keeps for working them.

Traditions

  1. Hellenistic astrology2nd century BCE–7th century CE

    The synthesis that invented the horoscope: ascendant, twelve places, aspects, lots, sect, and time-lords, worked in Greco-Roman Egypt, set out by Dorotheus and Vettius Valens, and rationalised by Ptolemy.

    System Architecture

    1. 01Whole-sign houses
    2. 02Sect: day and night charts
    3. 03The lots, Fortune first
    4. 04Time-lord periods

    Representative texts

    • Ptolemy, Tetrabiblos
    • Vettius Valens, Anthology
    • Dorotheus, Carmen Astrologicum
  2. Jyotisha (Indian)2nd century CE–present

    India's unbroken tradition: the sidereal zodiac, the twenty-seven nakshatras, planetary periods (dashas) that time the whole life, and a divisional-chart method of great refinement.

    System Architecture

    1. 01Sidereal zodiac with ayanamsa
    2. 02Nakshatras — the lunar mansions
    3. 03Vimshottari dasha periods
    4. 04Divisional (varga) charts

    Representative texts

    • Yavanajataka
    • Varahamihira, Brihat Jataka
    • Varahamihira, Brihat Samhita
    • Brihat Parashara Hora Shastra (late compilation)
  3. Chinese astrologyHan dynasty–present

    A parallel invention on different foundations: state astral omenology in the Han histories, read on an equatorial frame of twenty-eight lodges, and — from the Tang and Song — personal fate-calculation by the ten heavenly stems and twelve earthly branches, crossed into the sixty-fold cycle and read through the five phases in the Four Pillars of birth year, month, day and hour.

    System Architecture

    1. 01Stems and branches
    2. 02The sixty-year cycle
    3. 03Five phases, not four elements
    4. 04Four Pillars (BaZi)

    Representative texts

    • Han shu astronomical treatises
    • Yuan Hai Zi Ping
  4. Perso-Arabic and medieval Latin8th–17th century

    The Abbasid translators systematized Greek and Indian material into the astrology Latin Europe relearned from the twelfth century — horary and electional practice at full sophistication, mundane cycles of Jupiter and Saturn, and the dignities elaborated into a scored system.

    System Architecture

    1. 01Essential and accidental dignity
    2. 02Horary judgment
    3. 03Great conjunction cycles
    4. 04Quadrant house division

    Representative texts

    • Masha'allah, On Reception
    • Abu Ma'shar, Great Introduction
    • Bonatti, Liber Astronomiae
    • Lilly, Christian Astrology
  5. Modern and psychological1890–present

    Alan Leo simplified the craft around character; Rudhyar and the Jungians rebuilt it as a psychology of individuation; the Uranian and midpoint schools re-engineered its geometry; and from 1993 the traditional sources returned in new translation.

    System Architecture

    1. 01Character as destiny
    2. 02Outer planets as generational
    3. 03Midpoints and harmonics
    4. 04The traditional revival

    Representative texts

    • Alan Leo, The Art of Synthesis
    • Rudhyar, The Astrology of Personality
    • Project Hindsight translations

Chronology

How to read the chart

Each period is drawn to its extent on one shared axis, so a three-hundred-year epoch runs three times the length of a hundred-year one. The boundaries are conventional rather than exact: a bar marks where the surviving evidence sits, not the year a tradition began or stopped. The empty stretches are part of the record — but a gap here means this dossier holds nothing in that interval, not that nothing happened in it.

  1. c. 1800 BCE – 1000 BCE

    Omen watching

    Mesopotamian scholars compile celestial omens — eclipse, halo, planet rising — into the great series Enuma Anu Enlil: seventy tablets of if-then statements linking sky to kingdom. Astrology begins as state intelligence, not personal character.

    Fixed points
  2. Gap · 1000 BCE – 410 BCE · 590 yearsAbout this gap

    Not a void. Neo-Assyrian court scholars report the omens to Esarhaddon and Ashurbanipal in the seventh century; the compendium MUL.APIN is copied by 686 BCE; the Astronomical Diaries record the sky night by night from 652 BCE; and by about 400 BCE the zodiac of twelve equal thirty-degree signs, on which the first horoscopes are cast, has been defined.

    410 BCE

    The first birth chart

    A cuneiform tablet records planetary positions for a child born late in the fifth century — the earliest known natal horoscope. The sky's attention turns from the king to the individual.

    Fixed points
  3. Gap · 410 BCE – 150 BCE · 260 yearsAbout this gap

    Not a void. The cuneiform horoscopes run on from 410 to 69 BCE; Berossus, a priest of Bel, writes his Babyloniaca for Antiochus I and, Vitruvius says, opens a school on Kos; and Greek astronomy from Eudoxus onward builds the geometry the horoscope will use.

    2nd century BCE–2nd century CE

    150 BCE – 200 CE

    The Hellenistic synthesis

    In Ptolemaic and Roman Egypt the Babylonian zodiac meets Egyptian decans and Greek geometry: ascendant, twelve places, aspects, lots, and sect appear together as a working system — the horoscope as the West still recognizes it.

    Fixed points

  4. c. 150 CE

    Ptolemy's Tetrabiblos

    The astronomer of the Almagest writes astrology's most durable defense: a natural-philosophical account of celestial influence that will carry the art through fourteen centuries of respectability.

    In the Library of Alexandria ›

  5. 2nd–6th century

    150 CE – 600 CE

    India receives and transforms

    The Yavanajataka — 'sayings of the Greeks' — carries Hellenistic horoscopy to India, where it fuses with the nakshatra tradition and the sidereal frame into Jyotisha: the same bones, a different living body.

    Fixed points
  6. Gap · 600 CE – 750 CE · 150 yearsAbout this gap

    Not a void. Rhetorius of Egypt compiles the Hellenistic doctrine in the sixth or seventh century; in Sasanian Persia Dorotheus and Valens are read in Middle Persian, the road by which Dorotheus reaches Arabic; Severus Sebokht writes on the astrolabe in Syriac in the 660s; and Theophilus of Edessa, astrologer to the caliph al-Mahdi, carries the Greek art into the Abbasid court.

    750 CE – 1000

    The Arabic golden age

    Baghdad's translators and masters — Masha'allah, Sahl, Abu Ma'shar — systematize horary, perfect electional method, and build mundane astrology on Jupiter-Saturn conjunctions. Most of what medieval Europe knew, it learned from these books.

    Fixed points
  7. Gap · 1000 – 1100 · 100 yearsAbout this gap

    Not a void. al-Biruni writes his Book of Instruction in the Elements of the Art of Astrology (1029); Ibn Abi al-Rijal, Latin Haly Abenragel, composes the Kitab al-bari' at Kairouan; and al-Zarqali's work at Toledo prepares the Toledan Tables that Latin astrologers will compute with.

    1100 – 1300

    Latin Europe relearns the art

    Translation from Arabic restores astrology to the schools; it enters medicine, court, and calendar. Bonatti writes the Latin summa, and cathedral sculpture puts the zodiac over the doors.

    Fixed points
  8. Gap · 1300 – 1450 · 150 yearsAbout this gap

    Not a void. Cecco d'Ascoli is burned at Florence in 1327; the Paris medical faculty blames the plague of 1348 on the conjunction of Saturn, Jupiter and Mars in 1345; Nicole Oresme writes against judicial astrology in the 1360s; and Chaucer writes his Treatise on the Astrolabe about 1391.

    1450 – 1650

    Apex and rupture

    Print scatters ephemerides and almanacs; every court keeps an astrologer; Lilly's Christian Astrology gives English its horary classic in 1647 — while the new astronomy quietly removes the cosmology the art had rested on.

    Fixed points

  9. 1650 – 1890

    The long eclipse

    Astrology loses the universities and survives in almanacs and among antiquarian enthusiasts. The practice thins to sun-sign fortune-telling's ancestors — but the texts wait.

    Fixed points

  10. 1890 – 1930

    Revival through Theosophy

    Alan Leo rebuilds astrology around character — 'character is destiny' — and mass-produces it by mail; prosecuted twice under the Vagrancy Act, he moves the art decisively from event-prediction toward psychology. In 1930 the modern sun-sign column is born.

    Fixed points

  11. 1936 – 1980

    The psychological turn

    Rudhyar reads the chart as a seed-pattern of individuation; Jung uses synchronicity to give correspondence a modern name; Ebertin's midpoints and the Hamburg school re-engineer the geometry; and Michel Gauquelin's statistics (1955) put the art to the test and report a 'Mars effect' argued over for decades. The chart becomes a mirror more than an oracle.

    Fixed points

  12. 1993 – present

    The traditional revival

    Project Hindsight begins translating the Hellenistic corpus; whole-sign houses, sect, and time-lords return to working practice. For the first time, the tradition's whole depth — Babylonian to modern — is in print at once.

    Fixed points

Figures

  1. Berossus

    c. 300 BCE

    Babylonian priest credited with carrying the omen tradition to the Greek world — the legendary hinge between Mesopotamia and the Hellenistic synthesis.

  2. Claudius Ptolemy

    c. 100–170

    Author of the Tetrabiblos, astrology's great apologia, and of the Almagest that fixed its sky.

  3. Vettius Valens

    120–c. 175

    Working astrologer whose Anthology preserves more actual Hellenistic practice — with worked charts — than any other source.

  4. Abu Ma'shar

    787–886

    Baghdad's great systematizer; his Great Introduction defined the art for the Arabic world and, in translation, for Latin Europe.

  5. Guido Bonatti

    c. 1210–1296

    The Latin Middle Ages' most cited astrologer — consulted by cities and condottieri, placed in Dante's Inferno for it.

11 more figures (of 16)

  1. William Lilly

    1602–1681

    England's master of horary, whose Christian Astrology remains the working manual of the judgment of questions.

  2. Alan Leo

    1860–1917

    Father of the modern revival: character-centered, Theosophical, and twice prosecuted for it.

  3. Dane Rudhyar

    1895–1985

    Composer-philosopher who rebuilt astrology as a psychology of becoming — the chart as seed, not sentence.

  4. Dorotheus of Sidon

    1st century

    His Carmen astrologicum, a didactic poem on nativities and elections, survives whole only in an Arabic version made from Middle Persian; through it the Hellenistic method reached Baghdad.

  5. Firmicus Maternus

    fl. 334–337

    Sicilian senator whose Mathesis is the fullest Latin manual of Hellenistic astrology and the source of the Thema Mundi as the West knew it; as a Christian he later wrote against the pagan cults.

  6. Masha'allah

    d. c. 815

    Persian Jewish astrologer of Basra, one of those who elected the founding of Baghdad in 762; his short treatises on questions and reception were among the first Arabic astrology put into Latin.

  7. al-Biruni

    973–1048

    Polymath whose Book of Instruction in the Elements of the Art of Astrology (1029) is the clearest medieval primer, and whose India (1030) describes Jyotisha from the inside.

  8. Abraham ibn Ezra

    c. 1089–1164/67

    Wrote the most extensive body of astrological treatises in Hebrew and carried the Arabic art into the Jewish and Latin West.

  9. Marsilio Ficino

    1433–1499

    The third of his Three Books on Life (1489), 'on obtaining life from the heavens', turned astrology to the care of the soul through images, music and diet — the astral magic the archive's Agrippa episode follows.

  10. Johannes Kepler

    1571–1630

    Imperial mathematician who cast horoscopes, rejected most of the tradition, and kept the aspects as harmonic geometry, adding the quintile, biquintile and sesquiquadrate (Harmonices mundi, 1619).

  11. Michel Gauquelin

    1928–1991

    French psychologist whose birth-data statistics (from 1955) found almost nothing for the signs and a contested 'Mars effect' for sports champions.

Source texts

  1. Enuma Anu Enlil

    Mesopotamian

    The seventy-tablet omen series: the sky read as the gods' correspondence with the state.

  2. Tetrabiblos

    Hellenistic

    Ptolemy's four books: the natural-philosophical case for celestial influence, and the tradition's anchor of respectability.

  3. Anthology

    Hellenistic

    Valens' nine books of working technique with over a hundred example charts — the practitioner's counterpart to Ptolemy's theory.

  4. Brihat Parashara Hora Shastra

    Jyotisha

    Attributed to the sage Parasara and treated as foundational in modern practice — houses, dashas, the divisional charts — though the text as printed is a late compilation, far younger than its ascription.

  5. Great Introduction

    Perso-Arabic

    Abu Ma'shar's summa, the channel through which Aristotelian natural philosophy entered the art; his Persian conjunction cycles are set out in a separate book, On the Great Conjunctions.

7 more source texts (of 12)

  1. Christian Astrology

    Early modern

    Lilly's 1647 English classic — horary judgment taught through some thirty-five questions judged in full in Book II, and a nativity worked at length in Book III.

  2. The Astrology of Personality

    Modern

    Rudhyar's 1936 reformation: the birth chart as a whole-pattern of individuation rather than a list of fates.

  3. Carmen astrologicum

    Hellenistic, 1st c.; Arabic version

    Dorotheus' five books on nativities and elections, the main route of Hellenistic method into Arabic.

  4. Astronomica

    Latin, c. 10-20 CE

    Manilius' didactic poem, the earliest surviving astrological text in Latin.

  5. Mathesis

    Latin, c. 334-337

    Firmicus Maternus' eight books: the Thema Mundi (III.1) and the fullest Latin account of Hellenistic practice.

  6. Book of Instruction in the Elements of the Art of Astrology

    Perso-Arabic, 1029

    Al-Biruni's primer in questions and answers, from geometry to judgment.

  7. Disputationes adversus astrologiam divinatricem

    Renaissance, 1496

    Giovanni Pico della Mirandola's posthumous attack, which Kepler and the reformers of astrology answered for a century.

Glossary

The vocabulary this dossier uses, with the register each definition belongs to. Terms the archive has spoken about link into transcript search; terms treated more fully on this page point there instead.

Ascendant
The degree of the zodiac rising at the eastern horizon for a given moment and place — the hinge on which the whole chart turns. Search
SectHellenistic
The day/night division of Hellenistic practice: diurnal charts favor Sun, Jupiter, Saturn; nocturnal favor Moon, Venus, Mars. A planet's condition changes with the chart's sect. Search
Dignity
A planet's strength by zodiacal position — domicile, exaltation, triplicity, term, face — scored and weighed in traditional judgment. Search
Lot (Part)Hellenistic
A calculated point projected from an arc between two bodies, the Lot of Fortune first among many; most reverse their formula by sect. Search
AyanamsaSanskrit
The accumulating offset between tropical and sidereal zodiacs — about 24 degrees now, growing one degree every 72 years. Search
8 more terms (of 13)
NakshatraSanskrit
One of the 27 lunar mansions of Indian astrology, each spanning 13°20' — a finer zodiac keyed to the Moon. Search
Horary
The branch that answers a question from the chart of the moment it is asked — judgment without a birth time. Search
Great conjunction
The Jupiter-Saturn meeting every twenty years, the clock of traditional mundane astrology's epochs. Search
TriplicityHellenistic
The four groups of three signs a trine apart, each with planetary rulers by day and night; Ptolemy gives them winds, later authors elements. Search
Term (bound)Hellenistic
Unequal divisions of each sign assigned to the five planets; the 'Egyptian' terms are the commonest scheme. Search
JoyHellenistic
The house in which a planet rejoices: Mercury the first, the Moon the third, Venus the fifth, Mars the sixth, the Sun the ninth, Jupiter the eleventh, Saturn the twelfth. Search
AversionHellenistic
Signs that cannot see one another — adjacent, or five signs apart — Ptolemy's 'disjunct' signs; the modern semisextile and quincunx. Search
Thema MundiHellenistic
The birth chart of the world: Cancer rising and each planet in one of its own houses, a teaching device for the domiciles given by Firmicus Maternus. Search

Editorial noteThis dossier is an Aetherica editorial research layer. It is designed to support deeper pages, archive search, future bibliographies, and interactive diagrams. Historical claims, symbolic readings, and modern esoteric interpretations should remain clearly labeled as the library expands.

Continue

Adjacent currents

Path V · IntermediateAstrology and Cosmic OrderTo read the heavens as an ordered cosmos in which the human being takes part, rather than as a catalogue of predictions.6 stationsWalk the path

Adjacent subjects

Instruments that draw on Astrology

16 instrumentsDecan Calculator · Lunar Mansions · Celestial Timing · Planetary Day · Moon Phase · Election Planner · Zodiacal Hours · Planetary Hours · Fixed Stars · Astrolabe Compass · Taoist Calendar · Sundial · 24-Hour Clock · Planetary Correspondences · Geomantic Shield Chart · Sacred Calendar

In the Library of Alexandria