Atlas methods and sources

Calculations

Sunrise and sunset use Astronomy Engine 2.1.19 SearchRiseSet for an observer at the city centre, elevation zero, standard atmospheric refraction and a flat horizon. Moon phase and illuminated fraction are evaluated at the midpoint of the local civil day. Times are displayed to the nearest minute.

Days run from local midnight to the next local midnight using the runtime IANA time-zone rules. This preserves 23- and 25-hour days. Future government changes to time zones are not known in advance.

Astronomical results are estimates, not weather forecasts or religious observance decisions. Mountains, buildings, actual elevation and atmospheric conditions can change visible sunrise and sunset.

Coordinates reuse the established Aafnai Patro city-centre dataset in src/place/cities.ts. Date inventory is fixed at 50 cities × 40,000 consecutive dates. BS dates use the existing project month-length table; historical records come only from source-backed rows of the project history archive.

Astronomy Engine source and validation · IANA time-zone database