Struct CioLocator 

pub struct CioLocator { /* private fields */ }

Computes the CIO locator angle s for a given epoch.

The locator is model-dependent. Currently only IAU 2006A is implemented, which uses the IAU 2006 precession with IAU 2000A nutation.

Example

use celestial_core::cio::CioLocator;

// Compute s for J2000.0 + 0.5 centuries (year ~2050)
let locator = CioLocator::iau2006a(0.5);

// X, Y from CIP coordinates (typically from precession-nutation matrix)
let x = 1.0e-7;  // radians
let y = 2.0e-7;  // radians

let s = locator.calculate(x, y).unwrap();
// s is in radians, typically on the order of 10^-8

Implementations

impl CioLocator

pub fn iau2006a(tt_centuries: f64) -> Self

Creates a CIO locator using the IAU 2006/2000A model.

Parameters

• tt_centuries - TT (Terrestrial Time) as Julian centuries from J2000.0. Computed as (JD_TT - 2451545.0) / celestial_core::constants::DAYS_PER_JULIAN_CENTURY.

pub fn calculate(&self, x: f64, y: f64) -> AstroResult<f64>

Computes the CIO locator s given the CIP coordinates.

Parameters

• x - CIP X coordinate in radians (from NPB matrix element [2][0])
• y - CIP Y coordinate in radians (from NPB matrix element [2][1])

Returns

The CIO locator s in radians.

Errors

Returns an error if the epoch is more than 20 centuries from J2000.0, where the series expansion becomes unreliable.

Trait Implementations

impl Clone for CioLocator

fn clone(&self) -> CioLocator

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CioLocator

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

Formats the value using the given formatter.