How Jember's times are computed
For Jember (8.17° S, 113.69° E) Hourora computes the sun's position for each date and solves for each prayer: Fajr 20°, Isha 18°, with the authority's precautionary minutes. Asr uses the standard shadow rule. The times are shown in Western Indonesia Time, daylight saving included.
The default is the method usually published in Indonesia: Kemenag, Indonesia. You can choose another method, the Asr rule and the high-latitude rule above; the choice is saved on this device.