Methodology & Trust

How this experience calculates and interprets

The Sabian Story separates the deterministic from the interpretive, and is transparent about both. This page documents exactly what is calculated, how, and where the interpretation begins.

What are degree images?

The degree-image tradition associates one symbolic picture with each of the 360 degrees of the zodiac. The best-known example is the Sabian Symbols, first published in 1925 by Elsie Wheeler with Marc Edmund Jones and later re-imagined by Dane Rudhyar. Each image — “A woman rises from the sea,” “A bridge being built” — is a small picture meant for contemplation rather than prediction.

This testing preview does not use historical Sabian wording. It uses a project-owned original set of 360 degree images inspired by the same 360-degree idea. The active wording, titles, and commentary are generated for this project and are not claimed to be historical or canonical.

The zodiac and conventions used

  • Zodiac: Tropical zodiac (equinox-anchored, IAU standard positions).
  • House system: Placidus (Placidus is the MVP default. The choice is isolated in lib/chart/houses.ts behind the chart provider so it can be swapped without touching the rest of the application.)
  • Sabian degree convention: Degree-to-next convention. A position within a degree corresponds to the NEXT numbered Sabian degree. A position at exactly the boundary (0°00′00″ of a sign) corresponds to that sign's first degree (degree 1) — the leading edge convention.
  • Boundaries: 0°00′00″ of a sign → Sabian degree 1 of that sign (leading edge). 0°00′01″ of a sign → Sabian degree 1 of that sign (within the first degree). 29°59′59″ of a sign → Sabian degree 30 of that sign. 360.0000° (exactly 0° Aries) → global index 360, which is the same as Aries 1 via the 360≡1 boundary.
  • Ephemeris: astronomy-engine v2 — MIT License (Don Cross). https://github.com/cosinekitty/astronomy — a deterministic, VSOP87-based geocentric ephemeris.
  • North Node: the instantaneous osculating ascending node at the birth instant, derived from the Moon’s position and velocity vectors — never the descending node, and never a value sampled from a nearby node-crossing event.
  • Historical time: The local birth time is converted to UTC using the IANA time-zone database’s historical offsets for the exact birthplace and date — never a modern or assumed offset. DST gaps are rejected; ambiguous fall-back times expose both offset choices.

Deterministic calculation vs. AI interpretation

Every astronomical fact in a reading — the Sun’s longitude, the Moon’s degree, the Ascendant, the houses, the resulting Sabian degree — is calculated by deterministic code from a documented ephemeris. No AI model ever computes a planetary position, converts a time zone, or assigns a Sabian number.

AI (or, in demo mode, a deterministic mock) is used only for interpretation: reading the validated chart JSON and the symbol texts into reflective prose, story chapters, prompts, and artwork. It receives only the validated placements and symbol data, and its output is validated against a strict schema. The calculated facts are shown alongside every interpretation so the two can never be confused.

When the birth time is unknown

The Ascendant, Midheaven, and houses depend on the exact time of birth. When that time is not known, this application does not calculate or display them as facts, and never substitutes noon or any other assumed time. The Moon may be marked as potentially uncertain if it changes sign or Sabian degree during the local calendar day. The reading is then reduced to the placements that do not depend on the time of day.

Limitations and purpose

This is a testing-phase product. In demo mode the interpretation and artwork come from deterministic local fixtures and are clearly labeled as such. The active degree-image dataset contains 360 project-owned original phrases. They are not presented as historical wording by Elsie Wheeler, Marc Edmund Jones, or Dane Rudhyar, nor as an authorized Sabian corpus. The exact active image is shown in each reading and passed to the interpretation provider. Nothing in this experience is a medical, legal, or financial opinion, and nothing predicts your future. Its purpose is reflection and entertainment: a contemplative way to meet your own images.