Ephemeris and software versioning
The minimum version record required to reproduce planetary positions after libraries and reference data change.
Calculation contract · released 2026-08-18
Definition
An ephemeris result depends on the numerical model, data release, software implementation, configuration, and fallback behavior.
Calculation procedure
Retain engine name and version, data-file identifiers and hashes, selected calculation mode, request parameters, and any fallback taken.
Required inputs
- Engine and library version
- Ephemeris data release
- Configuration and target identifiers
- Runtime fallback policy
Maha convention
Maha production uses Astronomy Engine 2.1.19 and validates releases against a frozen independent corpus; Swiss Ephemeris is not a production dependency.
Uncertainty and edge cases
Two engines can agree within a declared envelope while differing enough to cross a discrete boundary. The continuous value must remain primary.
What this does not establish
Using a respected ephemeris does not validate claims derived from astrological labels.
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.
- Horizons System Manual
NASA/JPL Solar System Dynamics · 4.98d (2025-11-21)
Solar-system object identifiers, observing centers, time inputs, reference frames, corrections, output quantities, and stated ephemeris limitations.
Boundary: Horizons output is authoritative only with the complete query contract preserved; transformed or rounded values require their own provenance record.
- 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.
Related calculation contracts
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Questions that depend on this contract
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