Struct UT1 

pub struct UT1;

Universal Time 1 — Earth-rotation time axis.

Continuous in SI seconds, but UT1 ↔ TT requires a TimeContext because the mapping depends on the compiled ΔT model (and, in future phases, observed-ΔT data).

Accuracy and modeling limitations

UT1 conversions are backed by a piecewise ΔT model:

• Historical (pre-1973): polynomial approximations (Stephenson & Houlden 1986; Meeus Astronomical Algorithms). Accuracy varies from ±15 s (1620–1973) to ±hundreds of seconds (pre-948).
• Modern (1973 – horizon): USNO monthly determinations with linear interpolation. For the currently compiled bundle fetched 2026-04-18, the default monthly-ΔT path differs from the bundled daily IERS-derived path by less than 10 ms over the observed overlap through 2026-04-16, and by less than 0.2 s over the compiled short-range prediction overlap through 2027-04-24. See DELTA_T_PREDICTION_HORIZON_MJD for the hard stop.

This model is suitable for archival astronomy and telescope scheduling, but not for precision geodesy, VLBI, or pulsar timing, which require daily IERS EOP (DUT1) solutions. Use crate::TimeContext::with_builtin_eop when you want the most accurate bundled UT1 route.

Trait Implementations

impl Clone for UT1

fn clone(&self) -> UT1

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ConversionTarget<TAI> for UT1

type Output = Time<UT1>

fn try_convert(src: Time<TAI>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<TCB> for UT1

type Output = Time<UT1>

fn try_convert(src: Time<TCB>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<TCG> for UT1

type Output = Time<UT1>

fn try_convert(src: Time<TCG>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<TDB> for UT1

type Output = Time<UT1>

fn try_convert(src: Time<TDB>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<TT> for UT1

type Output = Time<UT1>

fn try_convert(src: Time<TT>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UT1> for TAI

type Output = Time<TAI>

fn try_convert(src: Time<UT1>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UT1> for TCB

type Output = Time<TCB>

fn try_convert(src: Time<UT1>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UT1> for TCG

type Output = Time<TCG>

fn try_convert(src: Time<UT1>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UT1> for TDB

type Output = Time<TDB>

fn try_convert(src: Time<UT1>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UT1> for TT

type Output = Time<TT>

fn try_convert(src: Time<UT1>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UT1> for UTC

type Output = Time<UTC>

fn try_convert(src: Time<UT1>) -> Result<Self::Output, ConversionError>

impl ConversionTarget<UTC> for UT1

type Output = Time<UT1>

fn try_convert(src: Time<UTC>) -> Result<Self::Output, ConversionError>

impl Debug for UT1

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

Formats the value using the given formatter.

impl Hash for UT1

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for UT1

fn cmp(&self, other: &UT1) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for UT1

fn eq(&self, other: &UT1) -> 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 PartialOrd for UT1

fn partial_cmp(&self, other: &UT1) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Scale for UT1

const NAME: &'static str = "UT1"

Display name of the scale. Used by Debug on Time.

impl ContinuousScale for UT1

impl CoordinateScale for UT1

impl Copy for UT1

impl Eq for UT1

impl StructuralPartialEq for UT1