Struct TT 

pub struct TT(/* private fields */);

Terrestrial Time representation.

Wraps a split Julian Date for high-precision time storage. TT is the primary time scale for geocentric ephemeris calculations.

Implementations

impl TT

pub fn new(seconds: i64, nanos: u32) -> Self

Creates TT from Unix timestamp components.

Converts seconds and nanoseconds since Unix epoch (1970-01-01T00:00:00) to TT Julian Date representation.

pub fn from_julian_date(jd: JulianDate) -> Self

Creates TT from a split Julian Date.

pub fn from_julian_date_raw(jd1: f64, jd2: f64) -> Self

Creates TT from raw Julian Date components.

Use when you have separate jd1/jd2 values and want to avoid intermediate JulianDate construction.

pub fn j2000() -> Self

Returns TT at J2000.0 epoch (2000-01-01T12:00:00 TT).

This is the fundamental epoch for modern astronomical calculations. JD = 2451545.0.

pub fn to_julian_date(&self) -> JulianDate

Returns the underlying Julian Date.

pub fn add_seconds(&self, seconds: f64) -> Self

Returns a new TT offset by the given number of seconds.

pub fn add_days(&self, days: f64) -> Self

Returns a new TT offset by the given number of days.

pub fn from_jd(jd: f64) -> TimeResult<Self>

Creates TT from a single-value Julian Date.

For high-precision work, prefer from_julian_date with split values.

pub fn julian_year(&self) -> f64

Returns the Julian year corresponding to this TT instant.

Julian year = 2000.0 + (JD - J2000_JD) / 365.25

pub fn centuries_since_j2000(&self) -> f64

Returns Julian centuries since J2000.0 (the T parameter).

This is the time argument used in IAU precession and nutation series. One Julian century = 36525 days.

Trait Implementations

impl Clone for TT

fn clone(&self) -> TT

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TT

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for TT

Formats as “TT {julian_date}”.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<JulianDate> for TT

Converts JulianDate to TT directly.

fn from(jd: JulianDate) -> Self

Converts to this type from the input type.

impl FromStr for TT

Parses TT from ISO 8601 format (e.g., “2000-01-01T12:00:00”).

Assumes the input string represents a TT instant directly.

type Err = TimeError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> TimeResult<Self>

Parses a string s to return a value of this type.

impl NutationCalculator for TT

fn nutation_iau2000a(&self) -> TimeResult<NutationResult>

fn nutation_iau2000b(&self) -> TimeResult<NutationResult>

fn nutation_iau2006a(&self) -> TimeResult<NutationResult>

fn nutation(&self) -> TimeResult<NutationResult>

impl PartialEq for TT

fn eq(&self, other: &TT) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PrecessionCalculator for TT

fn precession_iau2000(&self) -> TimeResult<PrecessionResult>

fn precession_iau2006(&self) -> TimeResult<PrecessionResult>

fn precession(&self) -> TimeResult<PrecessionResult>

fn bias_precession_matrix(&self) -> TimeResult<RotationMatrix3>

impl ToTAI for TT

Convert TT to TAI by subtracting the fixed 32.184 second offset.

The offset is subtracted from whichever Julian Date component has smaller magnitude to preserve maximum precision in the two-part representation.

fn to_tai(&self) -> TimeResult<TAI>

Convert to TAI.

impl ToTCG for TT

fn to_tcg(&self) -> TimeResult<TCG>

Convert TT to TCG by applying the L_G rate correction.

Uses L_G / (1 - L_G) as the rate ratio for the forward transformation. This ratio accounts for the fact that we’re computing TCG from TT, not vice versa.

At J2000.0, this adds about 0.506 seconds.

impl ToTDB for TT

fn to_tdb_greenwich(&self) -> TimeResult<TDB>

Convert to TDB using Greenwich Observatory as reference.

fn to_tdb_with_location(&self, location: &Location) -> TimeResult<TDB>

Convert to TDB using the specified observer location.

fn to_tdb_with_location_and_ut1_offset( &self, location: &Location, ut1_offset_seconds: f64, ) -> TimeResult<TDB>

Convert to TDB with location and UT1-UTC offset for maximum precision.

fn to_tdb_with_offset(&self, dtr_seconds: f64) -> TimeResult<TDB>

Convert to TDB using a pre-computed offset (TDB-TT) in seconds.

impl ToTT for TT

Identity conversion for TT.

fn to_tt(&self) -> TimeResult<TT>

Convert to Terrestrial Time.

impl ToUT1WithDeltaT for TT

fn to_ut1_with_delta_t(&self, delta_t_seconds: f64) -> TimeResult<UT1>

Convert to UT1 using the given Delta-T in seconds.

impl Copy for TT

impl StructuralPartialEq for TT