The most technical branch of Western astrology — built around midpoints and geometric symmetry rather than sign-based storytelling. Founded in Germany's Hamburg School, and refined into the more empirical discipline of Cosmobiology.
Two related but distinct schools. Classical Uranian astrology uses eight additional "hypothetical" planets beyond Neptune; Cosmobiology, developed later by Ebertin, keeps the midpoint method but works only with the real, observable planets.
Uranian astrology is a distinct, highly technical school built almost entirely around midpoints and the geometric symmetry between planetary positions. It reads a chart less as a narrative and more as a precision instrument, checking exact structural relationships between points. Its two best-known branches — classical Uranian astrology and the later, related Cosmobiology — share the midpoint-based method but differ on one point: whether to include eight additional "hypothetical" planets.
Founded in Germany in the early 20th century by Alfred Witte, working with Friedrich Sieggrün, the "Hamburg School" set out to make astrology more mathematically rigorous by focusing on precise angular relationships rather than looser sign-based symbolism. Witte's key innovation was systematising midpoint analysis into a full method, later expanded by his student Reinhold Ebertin.
Witte proposed eight additional points beyond Neptune to explain gaps in his midpoint calculations — never confirmed to physically exist, used symbolically. Classical Uranian astrology still uses all eight; most other schools dropped them.
A midpoint is the exact halfway point between any two chart factors — the Sun/Moon midpoint represents the blended energy of both. Uranian practice builds elaborate "midpoint trees," since a planet activating a midpoint is read as triggering both original factors at once. Witte developed the 90° dial — a chart wheel compressed to a quarter of the zodiac, bringing all hard-aspect relationships onto a single visible axis.
Reinhold Ebertin, a student of the Hamburg School, broke from Witte's hypothetical planets and developed Cosmobiology — keeping the rigorous midpoint method and 90° dial, but restricting analysis to the real, observable planets. His 1940 reference work The Combination of Stellar Influences remains a standard reference across both traditions.