commons-suncalc

A Java library for calculation of sun and moon positions and phases.

Features

Lightweight, only requires Java 8 or higher, no other dependencies
Android compatible, requires API level 26 (Android 8.0 "Oreo") or higher. For older Android versions, use commons-suncalc v2, which is similar to this version, but does not use the Java Date/Time API.
Available at Maven Central
Extensive unit tests

Accuracy

Astronomical calculations are far more complex than throwing a few numbers into an obscure formula and then getting a fully accurate result. There is always a tradeoff between accuracy and computing time.

This library has its focus on getting acceptable results at low cost, so it can also run on mobile devices, or devices with a low computing power. The results have an accuracy of about a minute, which should be good enough for common applications (like sunrise/sunset timers), but is probably not sufficient for astronomical purposes.

If you are looking for the highest possible accuracy, you are looking for a different library.

Quick Start

This library consists of a few models, all of them are invoked the same way:

ZonedDateTime dateTime = // date, time and timezone of calculation
double lat, lng = // geolocation
SunTimes times = SunTimes.compute()
        .on(dateTime)   // set a date
        .at(lat, lng)   // set a location
        .execute();     // get the results
System.out.println("Sunrise: " + times.getRise());
System.out.println("Sunset: " + times.getSet());

Read the online documentation for examples and API details.

See the migration guide for how to migrate from a previous version.

References

This library bases on:

"Astronomy on the Personal Computer", 4th edition, by Oliver Montenbruck and Thomas Pfleger
"Astronomical Algorithms" by Jean Meeus

Contribute

Fork the Source code at GitHub. Feel free to send pull requests.
Found a bug? Please file a bug report.

License

commons-suncalc is open source software. The source code is distributed under the terms of Apache License 2.0.

shred / commons-suncalc

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