Cosmobiology (Midpoints) (宇宙生物學)

The Midpoint Method — What Stands Between Your Planets, on the 90° Dial

Overview

Most astrology asks where the planets are. Cosmobiology asks a different question: where do their MIDPOINTS fall, and what is standing on them? The midpoint of two planets — the half-sum, the exact point halfway between them — is treated as a sensitive degree that fuses their two meanings into one. When a third planet sits on that midpoint, the three lock into a 'planetary picture', written C = A/B and read as a single combined force: Mars on the Saturn/Pluto midpoint, for instance, is one tight, recognisable signature rather than three separate placements. This is the method Reinhold Ebertin distilled in 1940 from Alfred Witte's Hamburg School, and its genius is compression — it throws away everything soft and ambiguous and keeps only the chart's hardest, tightest contacts. There are no trines or sextiles here, no wide orbs, no filler: only the 8th-harmonic hard aspects (conjunction, semisquare, square, sesquiquadrate, opposition), folded onto a 90° dial so that everything in hard aspect lands in the same place, read with orbs of about a degree. askTIAN computes the whole structure from the same precise tropical astronomy as its natal engine — the 13 classical factors, all 78 of their midpoints, every planetary picture within orb, the all-important Sun/Moon midpoint, and the midpoint trees organised by which planet they focus on — and reads it honestly as a symbolic language for reflection, never as a fixed forecast.

Origin & history

The midpoint method was born in the Hamburg School (the 'Uranian' school) founded by Alfred Witte in the years around the First World War. Witte's insight was that the empty point exactly between two planets behaves as if it carries their combined energy, and that planetary 'pictures' built from these half-sums describe a chart more precisely than aspects alone. Witte worked on a 90° dial — a physical instrument that folds the 360° zodiac into quarters so that conjunctions, squares and oppositions all coincide — and he and Friedrich Sieggrün added a set of hypothetical trans-Neptunian planets to the mix. Reinhold Ebertin, Witte's most influential successor, stripped the system back: he kept the midpoints, the hard aspects and the 90° dial, but discarded the hypothetical planets as unproven, and rebuilt the interpretive core on observable factors alone. He published the result in 1940 as 'Kosmobiologie', and his reference dictionary of midpoint combinations, 'The Combination of Stellar Influences' (COSI), became the standard handbook of the method — each combination given a principle, a psychological reading in positive and negative keys, and biological and sociological notes.

Cosmobiology became the backbone of 20th-century German-language astrology and spread widely through COSI's translation into English. Its appeal is exactness: because the method admits only tight hard aspects and treats midpoints as precise degrees, two practitioners working the same chart will identify the same handful of pictures — there is little of the latitude that makes aspect interpretation feel subjective. It also travelled well into other branches; the solar-arc directions of modern predictive astrology were popularised by Ebertin himself, and midpoint analysis is now a standard layer in software far beyond the cosmobiology community. askTIAN implements the Ebertin core and is candid about where practice varies. The set of factors is the classical thirteen — the Sun through Pluto, the North Node, the Ascendant and the Midheaven — and the hypothetical trans-Neptunians Ebertin rejected are deliberately excluded, as are Chiron and the asteroids, which postdate the method. The hardest convention question is the orb: COSI does not publish a single canonical table, and modern practice uses graduated orbs around a degree, tighter for the minor 45° and 135° aspects and for pictures not touching a personal point. askTIAN ships a transparent graduated scheme (about 1.5° for major aspects to a personal point, 1.0° for other majors, 0.5° for the 45°/135° series), allows a single uniform override, and says plainly that these numbers reflect mainstream practice rather than a verbatim Ebertin prescription. The interpretive keynotes are generated originally from keyword tables, since COSI's text is under copyright.

How it works

askTIAN converts the birth date, time, timezone and (optionally) place to a single instant and builds the chart on the tropical zodiac with its own Meeus-precision ephemeris — exactly the longitudes its Western natal engine returns, so the two agree by construction. The 13 factors are the ten planets, the North Node, and — when a birthplace is supplied — the Ascendant and Midheaven (without a place the analysis runs on the 11 planetary factors). It then forms all of their pairwise midpoints: with the angles that is C(13,2) = 78 half-sums, computed with signed-arc arithmetic so they are correct across the 0°/360° boundary, where naïve averaging fails — the midpoint of 350° and 10° is 0° Aries, not 180° Libra. For every midpoint it tests each remaining factor against the five 8th-harmonic HARD aspects (conjunction 0°, semisquare 45°, square 90°, sesquiquadrate 135°, opposition 180°) within the graduated orb, in a single pass that catches both the direct and the indirect (near and far) midpoint at once. Each hit is a planetary picture C = A/B, recorded with its exact orb, whether the apex occupies the midpoint directly, and whether it touches one of the 'Basic Five' personal points (Sun, Moon, Ascendant, Midheaven, Node) that cosmobiology reads first. The pictures are sorted tightest-first and grouped into midpoint trees keyed by their apex factor. The Sun/Moon midpoint — 'the point of personal integration', the marriage point, the single most important half-sum in the method — is surfaced on its own with whatever stands on it. Contacts to the Aries Point (0° of the cardinal signs, the 'world point') are reported too, but flagged as a Witte/Uranian extension rather than mixed into the Ebertin core. A transparent 0–100 score measures how concentrated and tight the chart's midpoint structure is — an emphasis index, never a fortune.

Good for

Use cases

Planetary-Picture Finder

Send a birth chart and the API returns every planetary picture within orb — apex factor, the pair it bisects, the hard aspect, the exact orb and whether it touches a personal point — sorted tightest-first. A deterministic spine for a midpoint feature, no LLM required.

Sun/Moon Midpoint Reading

The response highlights the Sun/Moon midpoint — its zodiac position and any factor standing on it — the half-sum cosmobiology treats as the most important in the chart, ideal for a focused 'core integration' or relationship feature.

Midpoint Trees by Apex

Pictures are grouped into trees keyed by the factor they focus on, personal points first, so an app can show 'everything that converges on your Sun' or 'on your Midheaven' as a single organised view.

Tunable Orb Analysis

Accepts a uniform orb override or uses the graduated default, and reports the orb scheme it applied and the exact orb of each picture — so a product can offer a 'tight vs wide' toggle and stay transparent about what changed.

Key terms

Midpoint (half-sum)
The point exactly halfway between two planets, treated as a sensitive degree that fuses their two meanings. Computed as the near (shorter-arc) half-sum, so it is correct across 0° Aries — the midpoint of 350° and 10° is 0°, not 180°. Every pair has a direct midpoint and an indirect one 180° away.
Planetary picture (C = A/B)
A three-factor combination in which a planet C stands in a hard aspect to the midpoint of A and B, read as a single combined force. Equivalent forms hold: if C = A/B then A = C/B and B = C/A — the three factors form one figure.
90° dial
The 4th-harmonic dial of the Hamburg School: the 360° circle folded into four 90° quadrants so that conjunctions, squares and oppositions all coincide. A factor and a midpoint that are square, opposed or conjunct land on the same dial degree, making hard contacts instantly visible.
Hard aspects (8th harmonic)
The only aspects cosmobiology uses: conjunction 0°, semisquare 45°, square 90°, sesquiquadrate 135° and opposition 180°. These are the multiples of 45° — the 8th harmonic — read as the dynamic, activating contacts; trines and sextiles are ignored.
Personal points (the Basic Five)
Sun, Moon, Ascendant, Midheaven and the North Node — the factors cosmobiology reads first. Pictures touching one of these are weighted most and given the widest orb, because they bear most directly on the person.
Sun/Moon midpoint
The half-sum of the Sun and Moon — 'the point of personal integration' and the classical 'marriage point', the single most important midpoint in the method. Any factor standing on it is read as central to identity and relationship.
Aries Point / world point
0° of the cardinal signs (Aries, Cancer, Libra, Capricorn), all of which fold to the same place on the 90° dial — Witte's 'world point' of contact with the public. askTIAN flags contacts to it as a Uranian extension, kept separate from the Ebertin core.

API

The askTIAN Cosmobiology API computes the full Ebertin midpoint structure for any birth chart on the same tropical ephemeris as its Western natal engine, so the factor longitudes agree by construction. It returns the 13 classical factors with their 90°/45° dial positions, all 78 midpoints, every planetary picture (C = A/B) at an 8th-harmonic hard aspect within the orb — apex, pair, aspect, exact orb, whether occupied directly and whether it touches a personal point — sorted tightest-first and grouped into midpoint trees by apex, plus the Sun/Moon midpoint with its occupants, the personal-point focus, the Aries-Point contacts (flagged Uranian), a transparent 0–100 midpoint-activity score and a fixed-section LLM reading. Hard aspects only; Chiron, the asteroids and the hypothetical trans-Neptunians are deliberately excluded and surfaced as out of scope. Provenance is honest: the half-sum arithmetic is locked by unit test against published worked examples and the modular-arithmetic invariants, the graduated orb scheme reflects mainstream practice rather than a verbatim Ebertin prescription, the Aries Point as a personal point is a Uranian addition, and the keynotes are generated originally since COSI's text is copyrighted. Midpoint pictures are a symbolic language for reflection, not a validated predictor, and depend on an accurate birth time. Set interpretation:false for structured data only.

Endpoint: POST /trpc/cosmobiology.compute — 7 TIAN Points. See the API documentation and Playground.