Reproducibility digests and calculation provenance
How canonical inputs, provider responses, software versions, and outputs become a tamper-evident calculation record.
Calculation contract · released 2026-08-18
Definition
A digest is a cryptographic hash of canonical serialized data. It detects change but does not by itself prove that the data were true.
Calculation procedure
Canonicalize the complete input and method contract, hash provider responses and output bundles, retain retrieval time and software version, and version any schema change.
Required inputs
- Canonical input contract
- Source response or local computed values
- Schema and software versions
- Hash algorithm
Maha convention
Maha uses SHA-256-prefixed digests in celestial provenance bundles and keeps limitations beside the hash.
Uncertainty and edge cases
Nondeterministic serialization, omitted defaults, or mutable “latest” source identifiers defeat reproducibility even when a hash is present.
What this does not establish
A valid digest proves integrity relative to its hashed bytes, not scientific validity or authorship.
Authoritative references
These sources establish the calculation vocabulary, data product, or transformation convention. They do not establish astrological interpretation.
- 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.
- 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.