Time Calculation for Prayer: Insights from Ikhtiṣaru Al-Falaki by Abu Muhammad Isa

Abstract: The book Ikhtiṣaru al-Falaki is a classical manuscript written by Abu Muhammad Isa in Arabic. This classical book consists of 94 pages and uses the classical tool rubu’ mujayyab as its calculation aid. In addition, Abu Muhammad Isa also used this book as a guide in creating his other work, "Schedule of Prayer Times for Eternity," which is still used in several mosques located near Dayah Darul Falah. Based on that background, this research aims to further examine the methods and their accuracy compared to other similar texts. The type of research used is qualitative research of a literature-based nature. (library research). The data collection technique was carried out through interviews and documentation. Next, it will be analyzed using descriptive and comparative analysis techniques. The research results show that the Kitab Ikhtiṣaru al-Falaki uses the method of hisab haqiqi taqribi and requires correction data because it has a difference of 0-6 minutes for Fajr time, 2-4 minutes for Isha time, and 0-5 minutes for Asr time when compared to the Kitab Durusul Falakiyah, which is similar to it.