Astro version 2.1.0

Bug Fixes

• Fix application startup when neither :tz nor :tzdata is configured. Astro.default_options/0 now falls back to time_zone_database: nil instead of raising CondClauseError. Calls that do not require a time zone database (e.g. time_zone: :utc) now work without any time zone library installed.

• Fix Astro.Supervisor.start_link/2 to gracefully handle the case where :tz_world is not installed. Previously the supervisor unconditionally referenced TzWorld.Backend.DetsWithIndexCache and crashed at startup when the optional dependency was missing.

Enhancements

• Add Astro.new_visible_crescent/3 to predict the visibility of the new crescent moon at a given location on a given date. Three published criteria are supported via the method argument:

  • :odeh (default) — Odeh (2006) empirical criterion based on 737 observations using topocentric ARCV and a Danjon limit of 6.4°.

  • :yallop — Yallop (1997) empirical criterion based on 295 observations using geocentric ARCV.

  • :schaefer — Schaefer (1988/2000) physics-based model computing the contrast between crescent brightness and twilight sky brightness against the human contrast detection threshold.

• Add Astro.new_visible_crescent/4 accepting atmospheric options for the Schaefer method (:extinction parameter).

• Add Astro.Ephemeris.Downloader which automatically downloads the JPL DE440s ephemeris file (~32 MB) from NASA NAIF on first application start and caches it under the user cache directory. The download URL and cache path can be overridden with the :ephemeris_url and :ephemeris application environment keys. If the download fails, Astro.Application.start/2 now returns a clear error message explaining how to install the file manually.