Penentuan Fasa Tanaffas dan Isfar Fajar Sidik.

The brightness or luminance of true dawn changes from when dawn light appears until sunrise. At the start of morning twilight after the night or at break of dawn, the intensity of the brightness is very low. The brightness intensity of dawn increases gradually in phases until it is bright. The phase of dawn or fajr in the Qur’an is mentioned as tanaffas and isfar in surah At-Takwir verse 18 (And the dawn as it breathes away the darkness) and Al-Mudatsir verse 34 (And by the dawn when it shines) respectively. These verses show that there are two types of brightness at dawn relating to tanaffas and isfar. These two different brightness levels show there are two phases of true dawn. This study aims to determine the time and depression angle of the Sun for the tanaffas and isfar phases and the brightness of the phases. This study was carried out by observation method at field locations in Malaysia and Indonesia. The instruments used were a thread window and an SQM-LU photometer. The results show that the tanaffas phase occurrs when white thread becomes visible and the isfar phase happens when black thread becomes visible. The tanaffas phase occurrs at the depression angle of the sun -16 ° to -14 ° and the isfar phase at an angle of -14 ° until sunrise. The average brightness of tanaffas phase is 19.44 mag arcsec-2 and isfar phase is 17.55 mag arcsec-2. The implication of this study gives the explanation about the words of tanaffas and Isfar in Al-Quran; and provides evidence of the truth of Al-Quran from the scientific perspective. [ABSTRACT FROM AUTHOR]