Classical Astronomy & Astrology
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Relationship astrology, rebuilt
Most apps lay two Sun-signs side by side and call it compatibility. This one reads the relationship itself — both charts weighed against each other through a five-phase Hellenistic engine that returns one honest verdict, and shows you every step that produced it.
A marriage is not a business partnership, and neither is a parent and child. So the engine holds twelve distinct bond modes, and each re-weighs which planets matter and reads its own topic of life. Marriage is judged from Venus, Mars and the seventh place; a working tie from Mercury, Saturn and the tenth; kinship from the luminaries and the fourth. Change the bond and the whole reading re-forms around it — the same two charts can be Fortified as friends and Contested as business partners, and the engine says both.
The bond is not scored by throwing aspects in a pile. It is built in order, each phase feeding the next, exactly as a Hellenistic astrologer would work a comparison by hand.
Phase I · Capacity
Before the bond is read, each native's own readiness is weighed from their own chart — the seventh place, the significators of union, and the relevant Lots. The same contact carries more between two who can hold the bond than between two who cannot.
Phase II · Temperament
The elemental dominant of each chart — sanguine, choleric, melancholic, phlegmatic — and how they sit together: ease by likeness, and a friction by contrast that can either deepen the bond or wear at it.
Phase III · Aspect testimony
Every whole-sign contact between the two charts, weighed by how central each planet is to this bond. The benefics build the architecture of support; the malefics mark the friction. Venus trine the Moon warms the regard; Mars square Mercury turns talk into contest.
Phase IV · House reception
Where one chart's planets fall in the other's houses — read both ways, because a bond is a meeting, not a vector. Venus in the partner's tenth eases shared standing; Mars in the seventh, friction at the partnership itself.
Phase V · Mechanism
The chain is stated in plain words — which testimonies carried, which were mitigated, and how they combine into the verdict — so you can check the judgement rather than trust it.
The verdict rests on a Bond Index from 0 to 100 — transparent and deterministic, not a black-box compatibility percentage. Fifty is neutral testimony, and the number swings freely with the strength of the classical contacts, uncompressed; because each mode reads different significators, it can swing hard from one bond to the next. It measures how strongly the classical testimony aligns — and nothing more: it is a measurement of doctrine, never a promise about your life.
From the index the engine names one of five bands — a structural description, not a school grade:
The tell of a serious engine is the middle band. A Contested bond carries real strength and real difficulty side by side, and the reading says so — instead of flattening both into a single flattering number. A significator wounded at the natal root can pull the grade down a step while the index still reads high, so a cautious word stands beside a strong figure. That honesty is the whole point.
Beyond the verdict, the engine renders the relationship as its own figure — a composite chart by the midpoint method, “the bond itself” cast as a third chart. A timeline carries it forward over the next fourteen days, twelve months and five years, with both natives' profected Lords of the Year. And in Synastry Sky you step onto the dome with both charts projected at once: colour-coded Ascendant beacons, both planet sets, the cross-aspects drawn as great circles arcing between the two charts, and the composite Sun and Ascendant among them.
Grounded in Ptolemy's one detailed synastry chapter (Tetrabiblos IV.5) and the common-Hellenistic house conventions of Valens, Firmicus and Manilius. The five-band scheme, the tier weighting and the Bond Index are this engine's own deterministic synthesis on that classical frame — and we tell you exactly where the tradition ends and our method begins.
The engine, applied
Here the engine is worked on a fictional pair, cast from the two charts below and read exactly as the app reads them. It is the clearest demonstration of what a single compatibility score cannot do: the same two people run from a Loving Marriage at the top of the scale to a Strained working bond near the floor. Every figure is computed from their charts, and it reproduces if you enter these two births yourself.
Nadia — 10 October 1991, 03:49, Mumbai · Theo — 24 October 1966, 09:52, Paris
Scored across all twelve bonds, the verdict runs the whole scale. Their marriage reaches Supported; most bonds read Contested; and as business partners, colleagues or hired help they fall to Impeded. The word is the classical verdict; the number is the strength of that bond's contacts on a fixed 0 to 100 scale, where fifty is neutral.
| Bond mode | Verdict | Band | Index |
|---|---|---|---|
| Marriage | Loving Marriage | Supported | 86 |
| Friendship | Cordial Acquaintance | Contested | 79 |
| Parent · Child | Mixed Inheritance | Contested | 79 |
| Sibling · Co-Heir | Civil Kin | Contested | 75 |
| Patron · Client | Conditional Patronage | Contested | 73 |
| Stranger · Foreigner | Indifferent Stranger | Contested | 73 |
| Mentor · Apprentice | Mixed Lessons | Contested | 69 |
| Family | Mixed Family Bond | Contested | 66 |
| Business | Strained Venture | Impeded | 49 |
| Colleague | Friction-Laden Workplace | Impeded | 41 |
| Servant · Employee | Strained Service | Impeded | 36 |
| Rivalry axis | Disarmed Rivalry | Severed | 20* |
* The rivalry axis is read on its own scale, alongside the bonds rather than among them; there a low number means little hostility, so “Disarmed” is the mild reading, not the harsh one.
This is the point most compatibility apps miss. Each bond mode reads its own significators: marriage weighs Mars, Venus, the Moon and the seventh place; work weighs Mercury and Saturn and the tenth; kinship the luminaries and the fourth. Between Nadia and Theo the marriage significators make strong contacts, led by Theo's Venus conjunct Nadia's Mars, the two significators of union joined. But the significators the working and kinship bonds lean on are wounded, so those bonds sink to Contested and Impeded. Same two charts, different significators, a verdict that swings from 86 to the thirties. One score could never say this.
Loving Marriage
BOND INDEX 86 · SUPPORTED · TESTIMONY TOTAL +16.74
Here the two lenses part, exactly as the engine is built to let them. The raw testimony, +16.74, clears the Fortified line, a “Devoted Union” on the contacts alone. But a compromised significator invokes the wounded-root rule and reduces the verdict one grade, to a Supported “Loving Marriage.” The high number stands; the cautious word stands beside it. That split is the honesty, not a glitch.
| Phase | Contribution to the verdict |
|---|---|
| Temperament | +1 |
| Aspect testimony | +13.12 |
| House reception | +2.62 |
| Applying | 0 |
| Natal capacity | reduces the grade one step (Fortified → Supported) |
Phase 0 · Capacity
Nadia's marriage significators are compromised and Theo's are impaired. The chain is only as strong as its weaker link, so the audit holds the verdict one grade below its raw testimony. It is why a total that reaches Fortified reads as Supported.
Phase 1 · Temperament · +1
Nadia is sanguine, Theo phlegmatic. They share the moist quality, so temperament adds a little rather than fighting: she runs quick and warm, he cool and even, and they meet on the same wet ground.
Phase 2 · Aspects · +13.12
The chief evidence, and the reason this bond clears the rest by a street. Venus conjunct Mars leads, with Venus warming Saturn and the Sun; Saturn's oppositions to Jupiter and Venus are the counterweight. The benefics carry it.
Phase 3 · Reception · +2.62
Theo's Moon lands in Nadia's seventh, the house of marriage (+3), but his Saturn lands there too (−3) and cancels it; Nadia's Venus and Jupiter fall in his eleventh. Both seventh-lords sit succedent, neither strong nor weak.
Phase 4 · Applying · 0
The chief contacts are separating, not applying. The engine reads the bond as one already formed and set, rather than one still tightening toward exact.
| Cross-chart contact | Classical testimony |
|---|---|
| Theo's Venus conjunct Nadia's Mars | The two significators of union joined: affection meets desire. The primary contact, and the chief support. |
| Nadia's Saturn opposite Theo's Jupiter | Restraint stands against expansion across the charts; the chief strain the marriage has to answer. |
| Theo's Venus trine Nadia's Saturn | His affection eases her discipline, a steadying, sweetening support. |
| Theo's Saturn opposite Nadia's Venus | His restraint cools her affection from across the chart. |
| Theo's Venus conjunct Nadia's Sun | His affection lends warmth to her very self, a qualified support. |
| Nadia's Saturn square Theo's Sun | Her discipline presses on his self at the right angle. |
After weighing every contact between the two charts, the judgement this classical rule set reaches: a marriage bond whose raw testimony reaches Fortified, carried chiefly by the conjunction of Venus and Mars across the significators of union, which draws the two together. A wounded significator reduces the grade one step, to a loving but weighted union. Its chief strain is Saturn's opposition to Jupiter, restraint set against expansion. The bond is strong in its affections and is asked, again and again, to answer for its Saturn.
Read the same two charts any other way and the verdict drops, and keeps dropping. As friends, a Cordial Acquaintance (79); as family, a Mixed Family Bond (66); as business partners, a Strained Venture (49); as colleagues, a Friction-Laden Workplace (41). The bond index runs from 86 at the top to the thirties at the floor. The marriage significators are strong between Nadia and Theo; the significators the other bonds depend on are wounded. That full sweep, from a loving marriage to a strained workplace in the one pair of charts, is the whole reason the engine reads twelve bonds instead of printing a single number.
Every line above is computed. No language model wrote any of it, and the same two births return the same reading every time.
Classical Astronomy & Astrology