Karaṇa calculation
How half-tithi elongation intervals map onto the repeating and fixed karaṇa sequence without premature rounding.
Calculation contract · released 2026-08-18
Definition
A karaṇa occupies 6° of Sun–Moon elongation. Sixty half-tithi slots are assigned to seven repeating and four fixed names under the declared sequence.
Calculation procedure
Normalize Moon-minus-Sun longitude, divide by 6°, floor to the absolute slot, apply the sequence table, and retain fractional progress and boundary distance.
Required inputs
- Sun and Moon longitude in the same frame
- Karaṇa sequence table
- Boundary policy
Maha convention
Maha calculates karaṇa from elongation, so a common ayanāṁśa cancels exactly as it does for tithi.
Uncertainty and edge cases
The classification can change quickly near a 6° boundary; rounded longitudes must not be used as inputs.
What this does not establish
A karaṇa name does not by itself produce a defensible activity verdict.
Authoritative references
These sources establish the calculation vocabulary, data product, or transformation convention. They do not establish astrological interpretation.
- Astronomy Engine
Don Cross (cosinekitty) · 2.1.19
Locally computed Sun and Moon positions derived from the VSOP87 and JPL-derived lunar theories, together with rise and set times, at the accuracy stated in the library documentation.
Boundary: Positions are computed in process rather than fetched from an authority, so a fact citing this source carries a digest over the computed values and not over a provider response body. Its accuracy is adequate for calendrical work and is not a substitute for a Horizons query where sub-arcsecond agreement matters.
- 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.