Equal-house convention
How equal houses differ from whole-sign houses even though both use twelve 30° sectors.
Calculation contract · released 2026-08-18
Definition
Equal houses place the first-house cusp at a selected anchor—commonly the ascendant degree—and add 30° for each subsequent cusp.
Calculation procedure
Choose tropical or sidereal frame and cusp anchor, normalize the anchor, generate twelve 30° cusps, and assign points by cyclic interval.
Required inputs
- Selected ascendant or alternative anchor
- Zodiac frame
- Boundary inclusion policy
Maha convention
Equal houses are documented for comparison but are not the current Maha Jyotiṣa production house system.
Uncertainty and edge cases
Calling both systems “30-degree houses” hides their difference: whole-sign house one starts at 0° of the rising sign, equal house one usually starts at the ascendant degree.
What this does not establish
Equal-house output should not be blended with whole-sign rules without a declared rule-pack dependency.
Authoritative references
These sources establish the calculation vocabulary, data product, or transformation convention. They do not establish astrological interpretation.
- Swiss Ephemeris general documentation
Astrodienst AG · 2.10 documentation, checked 2026-08-18
An independent ephemeris implementation, supported reference choices, house calculations, and its dual-license boundary.
Boundary: Maha does not bundle or call Swiss Ephemeris in production. Frozen conformance results are validation evidence, not permission to redistribute its software or data.