Pure-Rust astronomy library: time scales, IAU coordinate chain, ephemeris, WCS, FITS/XISF/SER I/O, telescope pointing models, star catalog, plate solving. Results are expected to match ERFA bit-for-bit.

core → time → coords → ephemeris · pointing · catalog · wcs → images → solver

celestial-core depends on nothing internal. Keep it that way.

• Math: libm::sin(x), never x.sin(). Constants come from celestial_core::constants, never std::f64::consts. Check celestial_core::math before writing a helper.
• Precision: tests use exact assert_eq! against reference values. A mismatch is a bug, so find the cause. Adding or widening any tolerance (including assert_ulp_le!) needs approval first.
• Imports: no prelude, and crate roots re-export nothing. Callers import from the defining module, e.g. celestial_core::matrix::{RotationMatrix3, Vector3}. This overrides the global "use a prelude" rule.
• Visibility: private, then pub(super) / pub(crate). Use pub only for real API.
• Errors: thiserror, and no panics in library code. NaN or non-finite input returns an error rather than garbage.
• Docs:
  • Don't add /// comments. User docs live in book/ (mdBook, rust,ignore examples).
  • Edit existing doc comments only when they're wrong.

cargo test --workspace
cargo clippy --workspace -- -D warnings            # CI runs both
cargo llvm-cov --features serde -p celestial-core  # coverage
rustfmt --edition 2021 path/to/file.rs             # format one file

The toolchain is pinned in rust-toolchain.toml. Optional features: serde (most crates), test-support (core), cli (catalog, ephemeris), parallel/simd/standard-formats (images).

references/ holds the IERS conventions and format specs. vsop2013/ holds the planetary series data.