Solar Time

Java Library, Calculate solar times like solar noon, sunrise, sunset, astronomical, nautical and civil dawn/dusks

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This work is heavily inspired by https://github.com/caarmen/SunriseSunset. The fundamental changes are:

• requires Java 11+,
• usage of Java 8 Time API (ZonedDateTime instead of Calendar),
• splitting return results of dawn and dusk and
• usage of Optional because Empty is a valid result for solar times.

Project Status

Example Usage

Entrypoint is the API. You can instatiate it via new API() to retrieve the SolarTime and SunStateChecker endpoints.

final var api = new API();
final var solarTime = api.getSolarTime();

final var now = ZonedDateTime.now();
final var latitude = 51.449680;
final var longitude = 6.973370;

solarTime.calculateNauticalDawn(now, latitude, longitude)
        .map(dateTime -> dateTime.withZoneSameInstant(ZoneId.systemDefault()))
        .map(ZonedDateTime::toLocalDateTime)
        .ifPresent(time -> LOGGER.info("Nautical Dawn: " + time));

INFO: Nautical Dawn: 2019-06-25T03:15:46

final var sunStateChecker = api.getSunStateChecker();
LOGGER.info("is 24-hour day: " + sunStateChecker.is24HourDayTime(now, latitude, longitude));

INFO: is 24-hour day: false

For more examples check the wiki