Crate tempoch_core 

Typed astronomical time primitives.

The central type is Time<S, F> (default F = J2000s), where S is a Scale marker (TT, TAI, UTC, UT1, TDB, TCG, TCB) and F is a TimeFormat tag (JD, MJD, J2000s, Unix, GPS).

tempoch makes a few explicit modeling decisions:

• Time<S, F> is an instant on a scale-specific axis; F only types external views (raw(), conversion targets), not a second storage layout.

• Time arithmetic follows affine rules: instant minus instant yields a duration; shifting an instant by a duration yields another instant.

• Internal storage is always a compensated (hi, lo) pair of J2000-based seconds so large epoch values can retain small corrections and sub-second detail.

• JD, MJD, J2000s, Unix, and GPS are conversion targets, not alternate stored encodings.

• UTC keeps special civil semantics: it is stored as a continuous instant and interpreted through the active UTC-TAI table when civil labels are needed.

• Time::new builds from a raw scalar when F is InfallibleFormatForScale for S (NaN panics; ±∞ allowed at rest). POSIX Unix instants still use Time::try_new / Time::try_new_with because decoding depends on leap-second tables.

• Time::try_new / Time::try_new_with surface domain decode failures only (UTC policy, leap seconds, …); callers must not pass NaN.

• UTC: civil (chrono) and POSIX (Unix); TAI: GPS (GPS)

• Unified targets: Time::to, Time::try_to, Time::to_with. Prefer try_to or to_with for Unix so positive leap-second instants are rejected when they are not representable as POSIX.

• Time::to_j2000s, Time::reinterpret, and aliases such as crate::JulianDate.

• JulianDate, ModifiedJulianDate, UnixTime, and GpsTime implement Into into default-tagged Time<S> / Time<UTC> / Time<TAI>, so APIs such as Period::try_new accept encoded endpoints without spelling Time::to_j2000s. J2000Seconds<S> is already Time<S>; no conversion needed.

See constats for epoch Time helpers, day/second scratch constants, and offsets.

Module map

• foundation: shared sealed traits, typed constants, and error types.
• model: Time, scale markers, and conversion targets.
• format: external format markers and format conversion traits.
• encoding: crate-local JD/MJD/J2000/Unix arithmetic helpers.
• earth: ΔT, EOP, and TimeContext Earth-rotation policy.
• data: runtime access to bundled and optionally refreshed time-data tables.
• period: interval and period-list algebra.
• features: optional serde/tagged/time-instant integration helpers.

Reference modules:

• earth::delta_t: piecewise ΔT (TT - UT1) model and modern tabular segment.
• earth::eop: public EOP sampling API over bundled IERS series.
• earth::context: immutable time-data snapshot plus conversion policy.

Re-exports

pub use earth::eop;

pub use foundation::constats;

pub use foundation::error;

pub use data::status::assert_fresh as assert_time_data_fresh;

pub use data::status::time_data_status;

pub use data::status::ActiveTimeDataSource;

pub use data::status::DataHorizons;

pub use data::status::FreshnessError;

pub use data::status::TimeDataStatus;

pub use earth::context::TimeContext;

pub use earth::delta_t::delta_t_seconds;

pub use earth::delta_t::delta_t_seconds_extrapolated;

pub use earth::delta_t::DELTA_T_PREDICTION_HORIZON_MJD;

pub use earth::eop::eop_end;

pub use earth::eop::eop_observed_end;

pub use earth::eop::eop_start;

pub use features::TimeInstant;

pub use format::FormatForScale;

pub use format::FormatOptions;

pub use format::FormatPrecision;

pub use format::GnssWeek;

pub use format::GnssWeekScale;

pub use format::GpsTime;

pub use format::InfallibleFormatForScale;

pub use format::J2000Seconds;

pub use format::J2000s;

pub use format::JulianDate;

pub use format::ModifiedJulianDate;

pub use format::TimeFormat;

pub use format::Unix;

pub use format::UnixTime;

pub use format::GPS;

pub use format::JD;

pub use format::MJD;

pub use foundation::constats::gps_epoch_jd_tai;

pub use foundation::constats::gps_epoch_jd_utc;

pub use foundation::constats::gps_epoch_tai;

pub use foundation::constats::iau_time_epoch_t0_jd;

pub use foundation::constats::j2000_jd_tt;

pub use foundation::constats::tdb_tt_model_high_accuracy_end_jd;

pub use foundation::constats::tdb_tt_model_high_accuracy_start_jd;

pub use foundation::constats::unix_epoch_jd;

pub use foundation::constats::unix_epoch_mjd;

pub use foundation::constats::utc_defined_from_mjd;

pub use foundation::constats::GPS_EPOCH_JD_UTC_DAY;

pub use foundation::constats::GPS_EPOCH_TAI_MINUS_UTC;

pub use foundation::constats::IAU_TIME_EPOCH_T0_JD_DAY;

pub use foundation::constats::J2000_JD_TT_DAY;

pub use foundation::constats::TDB_TT_MODEL_HIGH_ACCURACY_END_JD_DAY;

pub use foundation::constats::TDB_TT_MODEL_HIGH_ACCURACY_START_JD_DAY;

pub use foundation::constats::TT_MINUS_TAI;

pub use foundation::constats::UNIX_EPOCH_JD_DAY;

pub use foundation::constats::UTC_DEFINED_FROM_MJD_DAY;

pub use foundation::duration::DurationError;

pub use foundation::duration::ExactDuration;

pub use foundation::duration::NANOS_PER_SECOND;

pub use foundation::error::ConversionError;

pub use foundation::error::TimeDataError;

pub use model::scale::ContinuousScale;

pub use model::scale::CoordinateScale;

pub use model::scale::Scale;

pub use model::scale::BDT;

pub use model::scale::ET;

pub use model::scale::GPST;

pub use model::scale::GST;

pub use model::scale::QZSST;

pub use model::scale::TAI;

pub use model::scale::TCB;

pub use model::scale::TCG;

pub use model::scale::TDB;

pub use model::scale::TT;

pub use model::scale::UT1;

pub use model::scale::UTC;

pub use model::target::ContextConversionTarget;

pub use model::target::ConversionTarget;

pub use model::target::InfallibleConversionTarget;

pub use model::time::Time;

pub use period::complement_within;

pub use period::series::TimeSeries;

pub use period::series::TimeSeriesError;

pub use period::Interval;

pub use period::InvalidIntervalError;

pub use period::Period;

pub use period::PeriodListError;

Modules

data

Runtime access to bundled and optionally refreshed time-data tables.

earth

Earth-orientation and Earth-rotation conversion policy.

features

Optional or higher-level feature modules layered on top of the core time model.

format

Typed external formats for crate::Time.

foundation

Shared crate foundations used by every domain layer.

model

Core time model: instants, scales, and conversion targets.

period

Generic periods and interval-list operations.

Constants

MODERN_DELTA_T_OBSERVED_END_MJD