Struct TCG 

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

Geocentric Coordinate Time.

Wraps a JulianDate representing an instant in the TCG time scale. TCG is the coordinate time for the Geocentric Celestial Reference System, running ~6.97e-10 faster than TT (about 22 microseconds per year).

Implementations

impl TCG

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

Creates a TCG instant from Unix timestamp components.

Converts seconds and nanoseconds since 1970-01-01 00:00:00 to TCG. Note: This assumes the Unix timestamp is already in the TCG scale.

pub fn from_julian_date(jd: JulianDate) -> Self

Creates a TCG instant from a Julian Date.

pub fn j2000() -> Self

Returns the J2000.0 epoch (2000-01-01 12:00:00) in TCG.

pub fn to_julian_date(&self) -> JulianDate

Returns the underlying Julian Date.

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

Adds seconds to this TCG instant, returning a new TCG.

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

Adds days to this TCG instant, returning a new TCG.

Trait Implementations

impl Clone for TCG

fn clone(&self) -> TCG

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TCG

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

Formats the value using the given formatter.

impl Display for TCG

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

Formats the value using the given formatter.

impl From<JulianDate> for TCG

Conversion from JulianDate to TCG.

fn from(jd: JulianDate) -> Self

Converts to this type from the input type.

impl FromStr for TCG

Parses ISO 8601 formatted strings into TCG.

Accepts standard date-time formats like “2000-01-01T12:00:00”. Fractional seconds are supported.

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 PartialEq for TCG

fn eq(&self, other: &TCG) -> 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 ToTAI for TCG

Convert TCG to TAI by chaining through TT.

TCG has no direct conversion to TAI. This chains: TCG → TT → TAI.

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

Convert to TAI.

impl ToTCB for TCG

fn to_tcb(&self) -> TimeResult<TCB>

Convert TCG to TCB by applying the L_B rate correction.

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

The correction is computed relative to the 1977 reference epoch where TCG = TCB. Applies the correction to the smaller-magnitude JD component for precision.

impl ToTCG for TCG

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

Identity conversion. Returns self unchanged.

impl ToTT for TCG

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

Convert TCG to TT by removing the L_G rate correction.

Computes: TT = TCG - L_G * (JD_TCG - T0) * 86400 / 86400

The correction is subtracted because TCG runs faster than TT. At J2000.0, this removes about 0.506 seconds.

impl Copy for TCG

impl StructuralPartialEq for TCG