Crate tempoch 

Public façade over tempoch-core.

The crate root exposes the redesigned scale-only time model:

• Time<S> for typed instants on a given scale
• Scale markers such as TT, TAI, UTC, and UT1
• unified conversion targets via time.to::<Target>(), try_to, and to_with
• constats for epoch Time helpers plus canonical astronomical qtty::Day / qtty::Second facts

Modules

constats

Typed epoch and offset constants.

eop

Daily IERS Earth Orientation Parameters.

Structs

BDT

BeiDou Navigation Satellite System Time. BDT = TAI − 33 s (nominal, exact integer offset). Equivalently BDT = GPST − 14 s.

DataHorizons

Documented validity horizons of the currently active time-data bundle, expressed in MJD UTC days.

ET

NAIF/SPICE Ephemeris Time — compatibility marker.

ExactDuration

Exact-precision signed duration.

FormatOptions

Format options for ISO 8601 / RFC 3339 output.

GPS

GPS seconds since 1980-01-06T00:00:00 TAI.

GPST

GPS System Time. GPST = TAI − 19 s (nominal, exact integer offset).

GST

Galileo System Time. Nominally GST = TAI − 19 s (identical tick rate and integer offset to GPST today; broadcast inter-system offset GGTO is not modeled here).

GnssWeek

Decomposed GNSS week-number form.

Interval

Half-open time interval [start, end).

J2000s

SI seconds since J2000.0 TT (2000-01-01T12:00:00 TT).

JD

Julian Day (days since noon 1 January 4713 BC on the proleptic Julian calendar, TT axis by convention).

MJD

Modified Julian Day (JD − 2 400 000.5).

QZSST

Quasi-Zenith Satellite System Time. Nominally aligned with GPST (QZSST = TAI − 19 s). The QZSS ICD defines QZSST as steered to GPST; observed inter-system offsets are not part of the scale.

TAI

International Atomic Time. Continuous SI-second clock.

TCB

Barycentric Coordinate Time (IAU 2006 B3). Linear relation to TDB.

TCG

Geocentric Coordinate Time (IAU 2000 B1.9). Linear rate difference to TT.

TDB

Barycentric Dynamical Time.

TT

Terrestrial Time. The dynamical reference scale in this crate.

Time

A point in time on scale S, tagged with external format phantom F.

TimeContext

Explicit, immutable context for conversions that need one.

TimeDataStatus

Active time-data status captured from the runtime store.

TimeSeries

Half-open iterator [start, end) stepping by an ExactDuration.

UT1

Universal Time 1 — Earth-rotation time axis.

UTC

Coordinated Universal Time.

Unix

POSIX (Unix) seconds since 1970-01-01T00:00:00 UTC.

Enums

ActiveTimeDataSource

Source of the currently active time-data bundle.

ConversionError

Conversion error surface.

DurationError

Error type for fallible ExactDuration operations.

FormatPrecision

Subsecond rounding policy used by the formatter.

FreshnessError

Errors raised by freshness checks.

InvalidIntervalError

Error constructing an super::Interval with invalid bounds.

PeriodListError

Invariants on a period list.

TimeDataError

Error surface for runtime time-data operations.

TimeSeriesError

Error returned when a TimeSeries cannot be constructed.

Constants

DELTA_T_PREDICTION_HORIZON_MJD

MJD of the last compiled ΔT prediction point, on the UT1 axis (qtty::Day).

GPS_EPOCH_JD_UTC_DAY

GPS epoch JD value on the UTC axis: 1980-01-06T00:00:00 UTC.

GPS_EPOCH_TAI_MINUS_UTC

Exact TAI - UTC offset at the GPS epoch.

IAU_TIME_EPOCH_T0_JD_DAY

IAU 2000 B1.9 reference epoch T0 as a JD value on the TT axis.

J2000_JD_TT_DAY

J2000 epoch Julian Day value on the TT axis (JD 2 451 545.0 TT).

MODERN_DELTA_T_OBSERVED_END_MJD

NANOS_PER_SECOND

Nanoseconds per second; convenience constant for boundary code.

TDB_TT_MODEL_HIGH_ACCURACY_END_JD_DAY

End JD (TT axis) for the built-in TT↔TDB truncated-series accuracy band.

TDB_TT_MODEL_HIGH_ACCURACY_START_JD_DAY

Start JD (TT axis) for the built-in TT↔TDB truncated-series accuracy band.

TT_MINUS_TAI

Exact TT - TAI offset (32.184 s).

UNIX_EPOCH_JD_DAY

Unix epoch JD value on the UTC axis: 1970-01-01T00:00:00 UTC.

UTC_DEFINED_FROM_MJD_DAY

First MJD covered by the compiled UTC-TAI segment table, on the UTC axis.

Traits

ContextConversionTarget

Unified context-backed conversion target for Time<S, F>::to_with::<T>(&ctx).

ContinuousScale

Witness that a scale is both coordinate-bearing and physically continuous.

ConversionTarget

Unified conversion target for Time<S, F>::try_to::<T>().

CoordinateScale

Witness that a scale is continuous and supports direct arithmetic. UTC deliberately does not implement this: it has raw-axis accessors through CoordinateScale, but its civil interpretation remains leap-second-aware and table-driven.

FormatForScale

Witness that format F can encode and decode instants on scale S.

GnssWeekScale

Sealed trait providing the J2000-second offset of each GNSS scale’s epoch.

InfallibleConversionTarget

Unified infallible conversion target for Time<S, F>::to::<T>().

InfallibleFormatForScale

Witness that format F can encode scale S without a TimeContext.

Scale

Marker trait for a scientifically distinct time scale.

TimeFormat

Marker trait for an external time encoding such as JD or Unix time.

TimeInstant

Provides arithmetic on Time<S> values via seconds duration.

Functions

assert_time_data_fresh

Assert the active bundle is no older than max_age relative to now.

complement_within

Gaps inside outer that are not covered by any interval in periods.

delta_t_seconds

ΔT = TT − UT1, in seconds, for a Julian Day on the UT1 axis.

delta_t_seconds_extrapolated

ΔT = TT − UT1, in seconds, with quadratic tail-fit extrapolation beyond the last published prediction point.

gps_epoch_jd_tai

GPS epoch as Time<TAI, JD>.

gps_epoch_jd_utc

GPS epoch as Time<UTC, JD>.

gps_epoch_tai

GPS epoch as Time<TAI, J2000s>.

iau_time_epoch_t0_jd

IAU time epoch T0 as Time<TT, JD>.

j2000_jd_tt

J2000 epoch as Time<TT, JD>.

tdb_tt_model_high_accuracy_end_jd

End of the TT↔TDB model accuracy interval as Time<TT, JD>.

tdb_tt_model_high_accuracy_start_jd

Start of the TT↔TDB model accuracy interval as Time<TT, JD>.

time_data_status

Capture status for the currently active time-data bundle.

unix_epoch_jd

Unix epoch as Time<UTC, JD>.

unix_epoch_mjd

Unix epoch as Time<UTC, MJD>.

utc_defined_from_mjd

UTC definition boundary as Time<UTC, MJD>.

Type Aliases

EncodedTime

Historical name for Time<S, F> after the format-parameter merge.

GpsTime

GPS seconds on the TAI axis.

J2000Seconds

SI seconds since J2000.0 on scale S.

JulianDate

Julian day instant on scale S (JD tag).

ModifiedJulianDate

Modified Julian day instant on scale S.

Period

Typed time period on a given scale.

UnixTime

POSIX / Unix seconds on the UTC axis.