v1.9.0

specreduce 1.9.0

Released 2026-05-06.

This release introduces new 2D tilt correction classes for measuring
and removing spectral line tilt, adds a specreduce-specific Glossary
to the documentation, and deprecates the legacy terminology page.

Highlights

Tilt correction (#303)

Two new modules give specreduce a complete 2D tilt-correction workflow:

• specreduce.tilt_correction.TiltCorrection detects arc-lamp lines and
  fits a 2D model of the spectral tilt across the detector.

• specreduce.tilt_solution.TiltSolution stores the fitted model and
  provides:

  • bidirectional coordinate transforms between the detector frame and the
    tilt-corrected frame,
  • flux-conserving 2D resampling of the input image onto the rectified grid,
  • export of the solution as a gwcs.WCS object via the gwcs property,
  • reconstruction from a previously exported GWCS object via
    TiltSolution.from_gwcs().

The GWCS round-trip means tilt solutions can be persisted in standard
FITS/ASDF WCS containers and reloaded without specreduce-specific
serialisation.

Glossary (#304)

A new specreduce-specific Glossary consolidates the
terminology used across the package in a single reference page.

Other changes

• The legacy docs/terms.rst terminology document is deprecated and will be
  removed in a future release. A deprecation banner now points readers to the
  new Glossary. (#304)

Compatibility

No new minimum-dependency bumps in this release. The specutils ≥ 2.0 / astropy
≥ 6.0 / scipy ≥ 1.14 / photutils ≥ 1.11 floors introduced in 1.8.0 still apply.

Full changelog

See CHANGES.rst for the complete list of changes.