The app employs Japanese definitions for dawn and dusk, which were established by a samurai during the shogunate era, although they closely resemble civil twilight.
It offers the capability to determine the timing of sunrise, sunset, dawn, and dusk for your current location and major cities instantly.
In contrast, dawn starts and dusk ends when the sun’s geometric center is 7.3611° below the horizon.
Enabling the civil twilight option will make the dawn and dusk correspond to civil dawn and civil dusk.
This app serves as an alarm that provides notifications at dawn, sunrise, sunset, and dusk.