In Indonesia, many astronomers determine the criteria for the height of the Sun at dawn, its height varies from -18° to -20°. The Ministry of Religion of the Republic of Indonesia (RI) uses ijtihad - 20°. Lately, the discourse on the beginning of prayer times has resurfaced. The criteria for the initial height of the Fajr prayer time used by the Ministry of Religion of the Republic of Indonesia is -20° which is considered too dark, amid technological developments, the Ministry of Religion of the Republic of Indonesia still maintains a height of -20° below the horizon which adopted the old criteria.
In this study, the authors formulate two problem formulations, namely how is the method of determining the early dawn of the Ministry of Religion of the Republic of Indonesia, and what is the beginning of fajr prayer time for the Ministry of Religion from a fiqh and astronomy perspective?
This research is a qualitative research with the scope of library research, which is sourced from the results of interviews and documents, data collection is carried out by interviews and documentation. Furthermore, the data obtained were analyzed descriptively.
The findings of this study are that in detecting the presence of dawn as an early sign of dawn time, the Ministry of Religion of the Republic of Indonesia made observations using two types of instruments, namely Sky Quality Meter (SQM) and two types of ZWO ASI 120 cameras and DSLRs. Then return some algorithms for processing the processed data. The result is that the turning point of the light curve shows DIP -21, this is because Indonesia's atmosphere is in the equatorial region for a precautionary measure, so a height of -20 is taken as a form of ijtihadiyah from the Indonesian Ministry of Religion. Based on the fiqh paradigm, the Fajr prayer starts at the dawn of Sadiq, under conditions like in Indonesia, it means that it is still dark. If this is the case, then the Fajr prayer is relatively not a problem because there is a choice of time. Based on the astronomical basis, early dawn occurs when Earth's upper atmosphere breaks and reflects sunlight that illuminates the lower atmosphere. Starting the dawn time with a height of -20° below the horizon is classified as an astronomical dawn, marked by the dimming of the stars on the eastern horizon.

Ministry of Religion of the Republic of Indonesia; Beginning of Fajr Prayer; Altitude -20°