Calculate an uncorrected TT/arithmetic Davison relationship chart

Uncorrected Davison with a uniform-TT time mean and arithmetic latitude/longitude after +180 is canonicalized to -180. Not a shortest-arc/spherical midpoint or corrected-MC chart. No nodes, relocation, Placidus or interpretations. Unknown fields and ambiguous/nonexistent civil times reject. See DAVISON_CONVENTIONS.md.

Every admitted attempt reserves one standard monthly unit; failed or timed-out admitted attempts are not refunded. No automatic retries. Local implementation is not proof of deployment. Historical mode uses an explicit BCE/CE date object and UT1 conventions. Its response is the versioned historical envelope, not the modern UTC envelope. Read result for calculation fields and metadata for limits and uncertainty.