moira

Moira 5.1.1 — DE440 Historical Delta-T Repair

Release date: 2026-07-22

Public upgrade path: 5.1.0 to 5.1.1

Moira 5.1.1 fixes reader-backed historical chart computation when the active planetary kernel is the content-identified JPL DE440/LE440 product.

Moira’s historical Delta-T source is expressed on a declared lunar tidal acceleration basis. Before evaluating a reader-backed ephemeris, the engine translates that clock product to the active kernel’s admitted DE/LE basis. Version 5.1.0 admitted DE430/LE430 and DE441/LE441 but omitted DE440/LE440, so historical DE440 chart requests could raise _EphemerisTimeBasisError even though the kernel itself covered the requested epoch.

This release explicitly admits DE440/LE440 at -25.936 arcsec/cy², based on the JPL DE440/DE441 release record and the official Horizons historical Delta-T policy for that ephemeris generation. The mapping remains keyed by the SPK summary identity read from kernel content. Filenames do not establish identity, and no adjacent or unknown DE/LE release is inferred.

The behavioral scope is narrow:

Regression coverage exercises content-derived DE440 identity, historical Delta-T binding, UT1-to-TT conversion, and the retained refusal for an unadmitted coherent DE/LE identity.

Pushing the v5.1.1 tag triggers the repository’s GitHub Actions publication workflow, which builds the supported source distribution and platform/Python wheels and publishes them to PyPI.