Campanus House System Chart Calculator
Campanus houses divide the prime vertical, the great circle running directly overhead and underfoot at your birthplace, into twelve equal arcs, then project those onto the ecliptic. It's one of the oldest quadrant systems, used centuries before Placidus became the modern default.How it works ↓
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Campanus houses divide the prime vertical, the great circle passing directly overhead and underfoot at your birth location, into twelve equal sections, then project those onto the ecliptic. It's one of the oldest quadrant systems, predating Placidus by centuries.
Campanus divides the sky overhead and underfoot, not the equator
Campanus houses start from the prime vertical, an imaginary great circle that passes through the exact point overhead (the zenith) and the exact point underfoot (the nadir) at your birthplace, oriented through your horizon's due-east and due-west points. That circle gets divided into twelve equal 30-degree arcs, which are then projected onto the ecliptic using great-circle geometry to produce your house cusps.
This is a genuinely different reference circle than Placidus or Koch use. Those systems divide time along the celestial equator or via time arcs, while Campanus divides physical space directly overhead and underfoot at your specific location.
Campanus predates Placidus by roughly four centuries
The system is named for Johannes Campanus, a 13th-century mathematician and astronomer, and it was in active use well before Placidus (developed in the 17th century) became astrology's default quadrant system. Campanus belongs to the same broad medieval and Renaissance lineage of quadrant house systems as Regiomontanus, which followed it a couple of centuries later.
Some historians credit an earlier, less-documented source for the underlying prime-vertical method, with Campanus's name attached through later usage, but Campanus is the name that stuck.
Reach for Campanus for medieval or Renaissance-style technique, or prime-vertical-based delineation
Campanus is the natural choice if you're studying or practicing astrological techniques from the medieval or Renaissance period, since it was the house system in common use during that era. It's also relevant if you specifically want houses derived from the prime vertical rather than equatorial time or ecliptic-degree divisions.
How Campanus compares to Placidus, Koch, and Regiomontanus
Campanus, Regiomontanus, Placidus, and Koch are all quadrant systems that divide the space between your four angles into three houses each, but each starts from a different great circle: Placidus and Koch both work from equatorial or birthplace time arcs, while Regiomontanus divides the celestial equator geometrically rather than by time, and Campanus divides the prime vertical instead of the equator at all.
Because the reference circle is genuinely different, Campanus cusps for houses away from the angles will typically differ from Placidus, Koch, and even Regiomontanus, despite all four sharing the same quadrant structure.
Frequently Asked Questions
Does Campanus change my angles (Ascendant, MC, Descendant, IC)?
No, the four angles are calculated independently of house system and stay identical across Campanus, Placidus, Regiomontanus, and every other quadrant or non-quadrant system, only the intermediate cusps move.
Is Campanus considered more traditional than Placidus?
It's older by about four centuries, but "traditional astrology" as a modern label usually refers to Hellenistic-era Whole Sign technique rather than medieval quadrant systems like Campanus, Campanus is better described as a historical Western system than a traditional one in that specific sense.