Scenario kind pagesEdit on GitHubSource: docs/kinds/by-kind/lunar-time-offset.md

lunar-time-offset (scenario kind)

Scenario kind of the engine v0.38.0, family Lunar and cislunar. Advisory: analysis output from a research and engineering tool, not type-approved navigation equipment and not a safety-of-life service. Every label here is the engine's or the verification matrix's; a kind is MODELLED unless the matrix says otherwise (how a label is earned: the README's Evidence section).

What it does#

Modelled relativistic Earth–Moon clock rate (Lunar Coordinate Time, LTC/TCL): the secular LTC−TT rate from the self-potential difference and the Moon's kinetic term, reported with the published 56–59 µs/day band, plus the accumulated offset over a horizon.

One run of scenarios/lunar-time-offset.toml summarises as: lunar-time-offset | secular LTC−TT rate 57.04 µs/day (band 56–59) | self-pot 57.50 kinetic -0.46 | offset @ 1.00 d = 57.04 µs

Inputs#

From the schema (kshana kinds --json):

  • Required fields: none
  • Optional fields: epoch_year, epoch_month, epoch_day, horizon_days

The example scenarios/lunar-time-offset.toml sets, among others:

Field Value Unit
epoch_day 1 d
epoch_month 1 not stated
epoch_year 2000 not stated
horizon_days 1 day
kind lunar-time-offset text

Run it#

kshana scenarios/lunar-time-offset.toml

What it gives#

The scalar results of that run, with the units the engine states:

Result Value Unit
band_high 59 us/day
band_low 56 us/day
horizon_days 1 day
kinetic_us_per_day -0.458241 us/day
offset_at_horizon_us 57.043632 us
secular_rate_us_per_day 57.043632 us/day
self_potential_us_per_day 57.501873 us/day
tcg_tcl_secular_rate_ns_per_day 1498.889649 ns/day
topographic_spread_ns_per_day 26.0287 ns/day
The chart the engine writes for scenarios/lunar-time-offset.toml, kind lunar-time-offset

Evidence#

No matrix row names this kind by name; the label on its result is the engine's own, above.

The rows the run itself exercised, with the oracle the matrix gives each (the public sources are named there):

  • MODELLED Deterministic, scenario-hashed, SBOM + cross-platform golden gates. Oracle (ExternalDataset): SBOM conformance to the official CycloneDX 1.5 JSON Schema (+ valid SPDX identifiers) — an external published standard, zero validation errors over the full dependency graph; the FoM-determinism / byte-reproducibility part remains a pinned self-consistency check, so the row stays MODELLED
  • VALIDATED Relativistic Earth-Moon clock-rate (LTC/TCL) + TT/TAI/UTC chaining + ensemble. Oracle (ExternalDataset): Ashby & Patla 2024, 'A Relativistic Framework to Estimate Clock Rates on the Moon', Astronomical Journal 167:149 (NIST; basis for the IAU/IAG LunaNet LTC): Moon-surface self-potential L_m = 3.13881e-11 and secular total 56.02 µs/day matched as published numeric values; geocentric Moon speed cross-checked vs JPL DE440 (de440s.bsp via SPICE)

Limitations#

What the run's own report says is not modelled or not validated:

  • Honesty: MODELLED, not certified. The headline us/day figure is reference-dependent (Earth geoid W0 vs a lunar selenoid, the time-averaging window, neglected sub-us/day centrifugal/J2 corrections) -> a band, not a single number, is the honest output. Nothing here is validated to sub-nanosecond absolute accuracy or certified for operational timekeeping. The report also gives the accumulated LTC-TT offset over the hori (scenario file comment, lines 11 to 16)
  • Reproducibility & software assurance is MODELLED, not validated: a sub-claim is externally checked, but the whole capability composes modelled pieces, so the capability stays Modelled. (verification matrix (docs/MODELLED-RATIONALE.md))

See also#