Interpreting Fajr Ṣādiq Observations for Dawn Prayer Time Determination: A Comparative Atmospheric Framework Using Köppen Classification in Indonesia
DOI:
https://doi.org/10.15575/as.v28i1.45366Keywords:
fajr ṣādiq, dawn prayer time, Köppen climate classification, astronomical observation, Islamic legal reasoningAbstract
Accurate determination of the dawn prayer (ṣubḥ) time is dependent on the correct identification of fajr ṣādiq. Regardless of this fact, observational results remain inconsistent, owing to differences in observational methods and atmospheric conditions. Therefore, this study investigates fajr ṣādiq using AstroImageJ image analysis and Sky Quality Meter (SQM) measurements at three Indonesian locations representing Equatorial, Monsoon, and Savanna climates according to the Köppen classification. To achieve this objective, we collected sequential dawn images and sky brightness data simultaneously and analysed them independently. AstroImageJ consistently identified fajr ṣādiq at a solar depression angle of approximately −19° across all sites, while SQM measurements showed greater variability. These results suggest that fajr ṣādiq observations should be interpreted by considering observational methods and atmospheric characteristics alongside astronomical parameters. By introducing the Köppen climate classification as a comparative framework, this investigation advances understanding of astronomical parameters as scientific representations that support Islamic legal reasoning in determining the beginning of the dawn prayer, while preserving its normative foundations.
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