Module cio 

Celestial Intermediate Origin (CIO) based celestial-to-terrestrial transformations.

This module implements the IAU 2000/2006 CIO-based transformation from GCRS (Geocentric Celestial Reference System) to CIRS (Celestial Intermediate Reference System). The CIO approach is the modern replacement for the classical equinox-based method.

Components

• CipCoordinates: X/Y coordinates of the Celestial Intermediate Pole
• CioLocator: The CIO locator s, positioning the origin on the CIP equator
• EquationOfOrigins: Relates CIO-based and equinox-based right ascension
• CioSolution: Bundles all CIO quantities for a given epoch

Usage

For most use cases, compute a CioSolution from the NPB (nutation-precession-bias) matrix:

let solution = CioSolution::calculate(&npb_matrix, tt_centuries)?;
let cirs_matrix = gcrs_to_cirs_matrix(solution.cip.x, solution.cip.y, solution.s);

Re-exports

pub use coordinates::CipCoordinates;

pub use locator::CioLocator;

pub use origins::EquationOfOrigins;

Modules

coordinates

CIP (Celestial Intermediate Pole) coordinates for the IAU 2000/2006 precession-nutation model.

locator

CIO locator (s) for the IAU 2006/2000A precession-nutation model.

origins

Equation of Origins computation.

Structs

CioSolution

All CIO-based quantities for a given epoch.

Functions

gcrs_to_cirs_matrix

Builds the GCRS-to-CIRS rotation matrix from CIP coordinates and CIO locator.