Morphemeris DocsHouse Systems
All 23 house systems supported by the Morphemeris API.
House Systems
The system parameter on /v1/houses and /v1/chart accepts the system name or its single-character code.
Supported systems
| Name | Code | Notes |
|---|---|---|
placidus | P | Default. Most popular in Western astrology |
koch | K | Time-based, popular in German-speaking countries |
porphyrius | O | Trisection of quadrants |
regiomontanus | R | Space-based, used in horary |
campanus | C | Prime vertical division |
equal | E | Equal 30° houses from Ascendant |
whole_sign | W | Whole-sign houses (Hellenistic) |
vehlow_equal | V | Ascendant at middle of 1st house |
axial_rotation | X | Meridian system (alias: meridian) |
azimuthal | H | Horizontal system |
topocentric | T | Polich-Page system (alias: polich_page) |
alcabitius | B | Semi-arc based, medieval |
morinus | M | Equatorial system |
krusinski | U | Krusinski-Pisa system |
equal_mc | D | Equal houses from MC |
sunshine | I | Sunshine (Makransky) system |
sunshine_south | — | Sunshine, southern-latitude variant (name only) |
apc | Y | APC houses |
carter_poli_equatorial | F | Carter's Poli-Equatorial (alias: carter) |
savard_a | J | Savard-A |
pullen_sd | L | Pullen sinusoidal delta |
pullen_sr | Q | Pullen sinusoidal ratio |
sripati | S | Used in Indian astrology |
Codes follow the Swiss Ephemeris exactly, so a code copied from its documentation selects the same system here.
Changed 2026-08-24
Before this date pullen_sd and pullen_sr returned the wrong systems (Savard-A and Pullen SD respectively) because of a mislabel in the underlying library. They now return what their names say, and savard_a is available separately. If you stored cusps computed with either Pullen system before 2026-08-24, recompute them. The N code, which had been accepted for pullen_sr, is no longer accepted — use Q.
Example
# By name
?system=whole_sign
# By code
?system=WSystem names are case-insensitive.
Zodiacal vs. mundane house positions
Every chart response reports the house each body occupies. There are two ways to decide it, selected with house_position_mode on the chart endpoints:
zodiacal(default) — the body's ecliptic longitude is compared against the cusp longitudes alone. This is what a printed chart shows.mundane— the body is placed on the house system's actual cusp surfaces, honouring its ecliptic latitude (the Swiss Ephemerisswe_house_posalgorithm). Every body also gainshouse_position, the fractional house in[1, 13), andhousebecomes its floor.
Rules worth knowing:
- The fraction moves between modes even for bodies on the ecliptic. Zodiacal interpolates longitude between cusp longitudes; mundane measures progress through the house system's own geometry — semi-arcs, for Placidus. The two agree exactly at the cusps and drift by a few hundredths of a house in between: even the Sun's fraction moves by about 0.01.
- Latitude is the payload. Ten degrees of ecliptic latitude shifts a body by roughly 0.08 houses in mundane Placidus — enough to change the integer
housenear a cusp. The Moon, Pluto, and the asteroids are the bodies this matters for. - Sign-based systems are latitude- and mode-independent by construction: whole sign and the equal variants give identical placements in both modes.
- Mundane conventions are externally validated. The same engine's mundane astrocartography was checked against a published Astrodienst map ("Method: true latitude"): MC meridians agree within 0.2° and Moon/Pluto rising and setting lines within 0.5°.
- Mundane mode needs geocentric tropical ecliptic coordinates. Requests carrying
sidereal,equatorial,topocentric, orheliocentricare rejected, and the draconic chart — whose longitudes are rotated — rejects the mode outright.