Enum Scale 

#[non_exhaustive]
#[repr(u8)]
pub enum Scale {
    TAI = 0,
    TT = 1,
    ET = 2,
    TDB = 3,
    UTC = 4,
    UT1 = 5,
    UTCSpice = 6,
    UTCSofa = 7,
    GPS = 8,
    GST = 9,
    BDT = 10,
    QZSS = 11,
    TCG = 12,
    TCB = 13,
    LTC = 14,
    Custom = 15,
}

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

TAI = 0

TAI is the representation of an Epoch internally.

TT = 1

Terrestrial Time (TT) (previously called Terrestrial Dynamical Time (TDT)).

ET = 2

Ephemeris Time as defined by NASA/NAIF SPICE (identical to TDB).

TDB = 3

Barycentric Dynamical Time (TDB) — SPICE ephemeris time (ET is an alias for this).

UTC = 4

Universal Coordinated Time using modern IERS leap second rules.

UT1 = 5

UT1

UTCSpice = 6

Universal Coordinated Time using the SPICE historical model (fixed +9 s offset against TAI for all dates before 1972-01-01).

UTCSofa = 7

Universal Coordinated Time using the full SOFA historical model (varying fractional “rubber second” offsets from 1960–1971).

GPS = 8

GPS Time scale whose reference epoch is UTC midnight between 05 January and 06 January 1980.

GST = 9

Galileo Time scale.

BDT = 10

BeiDou Time scale.

QZSS = 11

QZSS Time scale has the same properties as GPS but with dedicated clocks.

TCG = 12

Geocentric Coordinate Time (TCG) – relativistic coordinate time in the Geocentric Celestial Reference System (GCRS).

TCB = 13

Barycentric Coordinate Time (TCB) – relativistic coordinate time in the Barycentric Celestial Reference System (BCRS).

LTC = 14

Coordinated Lunar Time (LTC) – NASA’s official lunar coordinate time scale (analogous to TCG). Defined from the NIST/Ashby & Patla (2024) relativistic framework adopted for Artemis and cislunar operations.

Lunar clocks on the selenoid run faster than terrestrial clocks by a constant secular rate of +56.02 µs per Earth day (L_M = 6.48378 × 10^{-10}). A small additional periodic variation exists due to lunar orbital eccentricity (±0.108 µs/day in instantaneous rate, ~±0.75 µs accumulated over one orbit). The periodic term is not part of the defining LTC conversion; it is handled via ClockModel / ClockDrift when utmost precision is required.

Custom = 15

Custom / user-defined type – for experimental or mission-specific timescales. Most powerful when paired with ClockModel (self-describing polynomial).

Implementations

impl Scale

pub const WIRE_SIZE: usize = 1

Size of the canonical wire representation in bytes.

pub const fn to_ut(&self) -> Self

pub const fn is_ut(&self) -> bool

Returns true if this scale accounts for leap seconds (or historical UTC civil time rules).

pub const fn is_gnss(&self) -> bool

Returns true if this scale is based off a GNSS constellation.

pub fn from_abbrev(s: &str) -> Option<Self>

Parse scale from abbreviation. Returns None for any non-ASCII input.

pub const fn abbrev(&self) -> &'static str

Short abbreviation used for formatting / display (e.g. “TAI”, “UTC”, “UTCSpice”).

pub const fn eq(self, other: Self) -> bool

Const-friendly equality comparison (does not rely on == for the enum itself).

pub const fn from_u8(v: u8) -> Option<Self>

Attempts to reconstruct a Scale from its wire byte representation.

Returns None for any value that does not correspond to a known variant. This provides safe deserialization from untrusted sources.

pub const fn to_wire_byte(self) -> u8

Returns the wire representation of this Scale as a single byte.

The returned byte is the repr(u8) discriminant of the enum. This is the canonical on-wire form used by [Dt] and [ClockModel].

Trait Implementations

impl Clone for Scale

fn clone(&self) -> Scale

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Scale

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

Formats the value using the given formatter.

impl Default for Scale

fn default() -> Scale

Returns the “default value” for a type.

impl Display for Scale

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

Formats the value using the given formatter.

impl Hash for Scale

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 Scale

fn cmp(&self, other: &Scale) -> 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 Scale

fn eq(&self, other: &Scale) -> 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 Scale

fn partial_cmp(&self, other: &Scale) -> 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 Copy for Scale

impl Eq for Scale

impl StructuralPartialEq for Scale