Crate tempoch 

Time Module

This module provides time-related types and abstractions for astronomical calculations.

Core types

• Time<S> — generic instant parameterised by a TimeScale marker.
• TimeScale — trait that defines a time scale (epoch offset + conversions).
• JulianDate — type alias for Time<JD>.
• JulianEphemerisDay — type alias for Time<JDE>.
• ModifiedJulianDate — type alias for Time<MJD>.
• Period<S> — a time interval parameterised by a TimeScale marker.
• Interval<T> — a generic interval over any TimeInstant.
• TimeInstant — trait for points in time usable with Interval.

Time scales

The following markers implement TimeScale:

Marker	Scale
JD	Julian Date
JDE	Julian Ephemeris Day
MJD	Modified Julian Date
TDB	Barycentric Dynamical Time
TT	Terrestrial Time
TAI	International Atomic Time
TCG	Geocentric Coordinate Time
TCB	Barycentric Coordinate Time
GPS	GPS Time
UnixTime	Unix / POSIX time
UT	Universal Time (Earth rotation)

ΔT (Delta T)

The difference ΔT = TT − UT is applied automatically by the UT time scale. Use Time::<UT>::new(jd_ut) for UT-based values, or construct any scale via from_utc() which routes through UT internally. The raw ΔT value (in seconds) is available via Time::<UT>::delta_t().

Structs

GPS

GPS Time — continuous day count since 1980-01-06T00:00:00 UTC.

Interval

Represents an interval between two instants.

JD

Julian Date — the identity scale.

JDE

Julian Ephemeris Day — dynamic Julian day used by ephemerides.

MJD

Modified Julian Date — JD minus 2 400 000.5.

TAI

International Atomic Time.

TCB

Barycentric Coordinate Time — the coordinate time for the BCRS.

TCG

Geocentric Coordinate Time — the coordinate time for the GCRS.

TDB

Barycentric Dynamical Time.

TT

Terrestrial Time — the basis for astronomical ephemerides.

Time

A point on time scale S.

UT

Universal Time — the civil time scale tied to Earth’s rotation.

UnixTime

Unix Time — seconds since 1970-01-01T00:00:00 UTC, stored as days.

Traits

TimeInstant

Trait for types that represent a point in time.

TimeScale

Marker trait for time scales.

Functions

complement_within

Returns the gaps (complement) of periods within the bounding outer period.

intersect_periods

Returns the intersection of two sorted, non-overlapping period lists.

Type Aliases

JulianDate

Julian Date — continuous count of days since the Julian Period.

JulianEphemerisDay

Julian Ephemeris Day — dynamical Julian day used by many ephemeris formulas.

ModifiedJulianDate

Modified Julian Date — JD − 2 400 000.5.

Period

Time-scale period alias.

UniversalTime

Universal Time — Earth-rotation civil time scale.

UtcPeriod

UTC interval alias.