House Overlay
Definition
A house overlay is a synastry step where you take one person's planets and see which houses they land in on the other person's chart — the houses being the twelve life areas a chart is divided into. You read each planet by zodiacal longitude against the receiving person's house cusps; only that person's cusps are used, and the planet's house in its own chart is set aside. In the evolutionary line of astrology the same step is called house transposition.
In Tradition
Modern Western relationship astrologers treat the house overlay as the spatial partner to inter-aspects: where inter-aspects tell you the quality of the energy passing between two charts, the overlay tells you which area of life it lands in. Practitioners give extra weight to planets that fall in a partner's 1st, 5th, 7th, 8th, and 12th houses — the houses most tied up with relating, intimacy, and the harder-to-see material a relationship stirs.
In Practice
To work a house overlay, you set up the receiving person's chart with its house cusps and drop the other person's planets onto it by longitude. Each placement reads as switching on that house's concerns for the receiving person — one partner's Venus on the other's tenth-house cusp, for instance, brings relationship themes into the field of public life and career. You run the overlay both ways, and the houses that keep getting lit up by tight planet-on-cusp contacts stand out as the relationship's natural areas of focus. House overlays are read together with the inter-aspect grid to give the full two-chart picture.
Historical Origin
House overlay analysis is a 20th-century Western technique with no classical forerunner. It is set out methodically in Howard Sasportas' The Twelve Houses (1985) and Robert Hand's Horoscope Symbols (1981), and runs through the evolutionary-astrology literature of Forrest and Tarnas. The Hellenistic, Arabic, and pre-modern Western sources compare two charts only by aspect contact, not by formally moving one chart's planets into the other's houses.
Etymology
Origin: English. Meaning: From over + lay — placing one chart framework upon another.
Further Reading
- Howard Sasportas, The Twelve Houses
- Robert Hand, Horoscope Symbols
- Sue Tompkins, Aspects in Astrology