A quadrant-based house division method developed by 15th-century astrologer Johannes Müller (Regiomontanus).
Definition
The Regiomontanus house system is a quadrant-based method of dividing the celestial sphere into 12 houses. It calculates house cusps by projecting the celestial equator onto the ecliptic using a system of great circles passing through the North and South celestial poles and the horizon. This system emphasizes the importance of the local meridian and horizon, making it particularly popular for horary astrology. Regiomontanus offers precise divisions that align well with observational astronomy, but like all house systems, it has limitations. For example, it may produce distorted house sizes at extreme latitudes.
In a chart
In a natal chart, the Regiomontanus system determines house cusps by dividing the celestial sphere into equal quadrants based on the horizon and meridian. Look for precise house cusps, especially in horary charts, but be cautious at extreme latitudes where distortions may occur.
Examples
- A horary chart using Regiomontanus to determine the outcome of a question.
- A natal chart with distorted house sizes at 70°N latitude.
History
The Regiomontanus system was developed by German astrologer and astronomer Johannes Müller (1436–1476), known as Regiomontanus. He introduced it in his 15th-century works to improve house division accuracy.