House Systems #

Kerykeion supports 23 different house systems from the Swiss Ephemeris. Each system divides the celestial sphere differently, affecting house cusp positions (though planetary positions remain the same).

Choosing a House System #

The choice of house system depends on your astrological tradition and preferences:

Modern Western: Placidus (default) or Koch
Traditional/Hellenistic: Whole Sign or Porphyry
Medieval: Regiomontanus or Alcabitius
Vedic/Jyotish: Whole Sign or Sripati
Horary: Regiomontanus
Extreme Latitudes (>60°): Whole Sign or Equal (Placidus/Koch fail near poles)

Complete House Systems Reference #

ID	Name	Description
`P`	Placidus	Default. Most popular in modern Western astrology. Time-based system that divides the diurnal arc into equal time segments. May fail at extreme latitudes.
`K`	Koch	Popular in Germany and for natal work. Similar to Placidus but uses birthplace latitude differently. Also fails at extreme latitudes.
`W`	Whole Sign	Ancient system where each house equals one entire zodiac sign. The Ascendant’s sign becomes the 1st house. Works at all latitudes. Preferred in Hellenistic and Vedic astrology.
`A`	Equal (from Asc)	Houses are exactly 30° each, starting from the Ascendant degree. Simple and works at all latitudes.
`D`	Equal (from MC)	Equal 30° houses with the MC on the 10th house cusp.
`V`	Equal/Vehlow	Equal houses with the Ascendant in the middle of the 1st house rather than at its cusp.
`N`	Equal/1=Aries	Fixed houses where 0° Aries is always the 1st house cusp.
`O`	Porphyry	Simple quadrant-based system. Divides each quadrant into three equal parts. Ancient and reliable.
`R`	Regiomontanus	Medieval space-based system. Standard for horary astrology. Divides the celestial equator.
`C`	Campanus	Space-based system using the prime vertical. Popular among some traditional astrologers.
`B`	Alcabitius	Medieval semi-arc system. Was standard in Arabic and medieval European astrology.
`M`	Morinus	Equator-based system. Unique in that the Ascendant is not necessarily on the 1st house cusp.
`T`	Polich/Page (Topocentric)	Similar to Placidus but accounts for the observer’s exact position on Earth. Very accurate for the Moon.
`S`	Sripati	Vedic-influenced system. Midpoint-based similar to Porphyry.
`H`	Horizon/Azimuth	Based on the local horizon and azimuth circle.
`I`	Sunshine	Modern system based on solar position.
`i`	Sunshine/Alternate	Alternate calculation of the Sunshine system.
`L`	Pullen SD	Modern Sinusoidal Delta system.
`Q`	Pullen SR	Modern Sinusoidal Ratio system.
`U`	Krusinski-Pisa-Goelzer	Modern house system.
`X`	Axial Rotation/Meridian	Based on the meridian circle.
`Y`	APC Houses	Astrological PC houses system.
`F`	Carter Poli-Equatorial	Rarely used system developed by Charles Carter.

Examples #

Birth Chart with Morinus House System #

from pathlib import Path
from kerykeion import AstrologicalSubjectFactory
from kerykeion.chart_data_factory import ChartDataFactory
from kerykeion.charts.chart_drawer import ChartDrawer

morinus_subject = AstrologicalSubjectFactory.from_birth_data(
    "John Lennon - House System Morinus", 1940, 10, 9, 18, 30,
    lng=-2.9833, lat=53.4, tz_str="Europe/London",
    online=False,
    houses_system_identifier="M",
)
data = ChartDataFactory.create_natal_chart_data(morinus_subject)
chart = ChartDrawer(data)

out_dir = Path("charts_output")
out_dir.mkdir(exist_ok=True)
chart.save_svg(output_path=out_dir, filename="john-lennon-morinus")

The output will be:

John Lennon - House System Morinus

Birth Chart with Whole Sign Houses #

from pathlib import Path
from kerykeion import AstrologicalSubjectFactory
from kerykeion.chart_data_factory import ChartDataFactory
from kerykeion.charts.chart_drawer import ChartDrawer

whole_sign_subject = AstrologicalSubjectFactory.from_birth_data(
    "John Lennon - Whole Sign", 1940, 10, 9, 18, 30,
    lng=-2.9833, lat=53.4, tz_str="Europe/London",
    online=False,
    houses_system_identifier="W",
)
data = ChartDataFactory.create_natal_chart_data(whole_sign_subject)
chart = ChartDrawer(data)

out_dir = Path("charts_output")
out_dir.mkdir(exist_ok=True)
chart.save_svg(output_path=out_dir, filename="john-lennon-whole-sign")

Check House System Name on a Subject #

from kerykeion import AstrologicalSubjectFactory

subject = AstrologicalSubjectFactory.from_birth_data(
    "Johnny Depp", 1963, 6, 9, 0, 0,
    lng=-87.1112,
    lat=37.7719,
    tz_str="America/Chicago",
    online=False,
    houses_system_identifier="P",  # Placidus
)

print(subject.houses_system_name)
# Output: Placidus

Comparing House Systems #

from kerykeion import AstrologicalSubjectFactory

# Same birth data, different house systems
systems = ["P", "K", "W", "R"]

for system_id in systems:
    subject = AstrologicalSubjectFactory.from_birth_data(
        "Test", 1990, 6, 15, 12, 0,
        lng=-0.1276, lat=51.5074, tz_str="Europe/London",
        online=False,
        houses_system_identifier=system_id,
    )
    print(f"{subject.houses_system_name}:")
    print(f"  1st House: {subject.first_house.sign} {subject.first_house.position:.1f}°")
    print(f"  10th House (MC): {subject.tenth_house.sign} {subject.tenth_house.position:.1f}°")

Output:

Placidus:
  1st House: Vir 24.5°
  10th House (MC): Gem 25.3°
Koch:
  1st House: Vir 24.5°
  10th House (MC): Gem 25.3°
Whole Sign:
  1st House: Vir 0.0°
  10th House (MC): Gem 0.0°
Regiomontanus:
  1st House: Vir 24.5°
  10th House (MC): Gem 25.3°

Note: The Ascendant and MC remain the same across most systems - only the intermediate house cusps differ.

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