Sunday is an astronomical clock that displays the following information:
- Sunrise, sun peak and sunset
- Azimuth (horizontal direction) to the sun, sunrise and sunset
- Blue hour for photographers
- Civil, nautical and astronomical twilight
- Beginning of the Sabbath (Shabbat)
- Islamic prayer times (7 calculation methods)
- Compass with reference direction (for example to Mecca)
- Solar compass
- Horae Temporales / Zmanim ("Jewish Clock") / Hebrew Hour
- Night hunting ban times in Germany

Times are displayed either on a classic 24-hour dial, an am/pm-dial with 2 x 12 hours or on a unique double dial with 12- and 24-hours.

Use Sunday as app, wallpaper or widget.

The location is set via the internal GPS / WiFi receiver, Google Maps, an integrated city map or manually.

Especially for use as a background image or for the lock screen, a dark design can be selected.

By swiping on the screen, the time and date can be simulated. In this way, the cosmic rhythms and relationships of the sun can be discovered and studied in every hour and every day of the year for every place in the world. This simulation can also run automatically as an animation.