Astroislamica: Journal of Islamic Astronomy
Vol. 5 No. 1 (2026): Astroislamica: Journal of Islamic Astronomy (June)

Comparative Prayer Time Computation: Nailul Watar, Ephemeris, and Istiwa’ Method

M. Saifulloh (Universitas Islam Negeri Walisongo Semarang)
Ahmadi Syifaul Anam (Universitas Islam Negeri Walisongo Semarang)
Jundil Ikrom (Universitas Islam Negeri Walisongo Semarang)
Agus Solikin (Universitas Islam Negeri Sunan Ampel Surabaya)
Ahmad Adib Rofiuddin (Universitas Islam Negeri Walisongo Semarang)



Article Info

Publish Date
04 Jun 2026

Abstract

Investigates the accuracy and consistency of prayer time calculations from both classical Islamic texts and modern astronomical data. I used a qualitative-comparative field research design, with Nailul Watar by KH. Ahmad Asrori, as the primary classical source, and the 2022–2023 astronomical ephemeris data, calculated using Akh. Mukkaram's Astrology. I also included supporting references on Islamic astronomy and prayer times. To collect data, I documented and analyzed the two methods before empirically validating them. The results show that the Nailul Watar method provides highly accurate calculations of Zuhr and Asr prayer times, with discrepancies from the ephemeris results measured in seconds and never exceeding one minute, without needing additional safety margins. Validation using the Istiwa' stick confirmed that the method meets the fiqh standards commonly used by Indonesian scholars, although observations showed that shadows appeared slightly earlier than the calculated times. The study suggests that further research be conducted by combining computational modeling of both methods and incorporating shadow-length data to improve precision in future prayer time determinations.

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Journal Info

Abbrev

ASTROISLAMICA

Publisher

Subject

Religion Astronomy

Description

Astroislamica: Journal of Islamic Astronomy is a journal that studies Islamic astronomy and Islamic laws related to astronomy. Astroislamica focuses on Islamic astronomy topics such as Qibla direction, prayer times, calendars, and eclipses through multiple perspectives, including Islamic law, ...