Astronomical and editorial sources

Calculation results are generated locally. External references are used for definitions, independent event-time validation and media-rights checks.

Astronomical calculations and validation

Astronomy Engine documentation and source — phase angle, illumination and principal-event calculations.
U.S. Naval Observatory: Dates of Primary Phases of the Moon — independent event-time fixtures.
U.S. Naval Observatory: phases and illuminated fraction — terminology and phase definitions.
IANA Time Zone Database — civil time-zone identifiers and transition rules consumed by the runtime.

Eclipse and image sources

A source collection does not grant one licence to every file. The licence and credit for an individual image must be checked before publication.

Read the calculation and validation methodology.