A popular method of house division in astrology that calculates houses based on time rather than space.
Definition
The Placidus house system is one of the most widely used methods of dividing the astrological chart into twelve houses. It calculates house cusps by projecting the earth's rotation onto the ecliptic, dividing houses based on the time it takes for a degree of the zodiac to rise or set over the horizon. This makes it a time-based system rather than a spatial one, meaning that the size of the houses can vary significantly depending on the latitude of birth. Symbolically, the unequal house sizes reflect the subjective experience of time and personal development. While it works well in most cases, this system can produce extreme distortions in polar regions, where houses may become excessively large or small.
In a chart
In a natal chart using the Placidus system, look at the house cusps to observe how they vary in size. Pay attention to extreme latitudes, where houses may appear distorted. Unequal houses are common, and intercepted signs may occur when an entire zodiac sign is contained within one house.
Examples
- A natal chart with the 1st house much larger than the 2nd house, reflecting Placidus's unequal division.
- A chart where Pisces is fully intercepted in the 3rd house, typical in Placidus at certain latitudes.