# Malaysia and Indonesia Studies

## Kassim Bahali et al. 2018 (DSLR Study)

**Paper:** Kassim Bahali, N.F., et al. "Determination of Fajr and Isha prayer times based on
astronomical observation at low latitude." *Sains Malaysia*, 47(11): 2797-2805, 2018.

**Location:** Kuala Lumpur and surrounding Malaysia/Indonesia sites (2°N-7°S range)
**Method:** DSLR astrophotography + SQM (Sky Quality Meter) sky brightness
**Data:** 64 observation days, February-December 2017

**Key result:** Mean Fajr depression = **16.67°** (range 13.9°-19.8°)

The DSLR + SQM combination is methodologically stronger than naked-eye only. The SQM
provides an objective measure of sky brightness that eliminates observer subjectivity.
At near-equatorial latitudes (2°-7°), the Sun rises and sets at a steep angle through the
horizon, producing very short, sharp twilight transitions.

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## Saksono 2020 (Depok, Indonesia)

**Paper:** Saksono, T. "Fajr prayer time determination using the Sky Quality Meter."
*NRIAG Journal of Astronomy and Geophysics*, 9(1): 238-244, 2020.

**Location:** Depok, West Java, Indonesia (6.4°S, 106.83°E, 65m)
**Method:** SQM sky brightness monitoring; 26 nights June-July 2015
**Result:** ~16° mean Fajr depression

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## Hamidi 2007-2008 (Malaysia Isha Study)

**Source:** Zety Sharizat Hamidi, *Determination of Isha prayer time based on shafaq abyad in
Malaysia.* Academia.edu, 2008.

**Location:** Two sites:
- Kuala Lipis: 4.183°N, 102.040°E, 76m (east coast)
- Port Klang: 3.004°N, 101.403°E, 5m (west coast)

**Method:** Naked-eye observation of Shafaq al-Abyad disappearance; May 2007 - April 2008
**Result:** Isha (Shafaq Abyad) consistently at approximately **16°-17°** depression

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## OIF UMSU (Medan, North Sumatra 2017-2020)

**Location:** OIF (Observatory of Islamic Fajr) at University of Muhammadiyah North Sumatra,
Medan (3.595°N, 98.672°E, 22m)
**Method:** SQM photometry; hundreds of observation days
**Proposed angle:** 16.48° for Indonesian national standard

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## Key Pattern: Equatorial Sites Yield Higher Angles

All Malaysia/Indonesia studies find Fajr at ~16°-17°, compared to ~13°-14° in Birmingham
and the UK. This is a systematic and significant pattern:

| Latitude | Representative Site | Mean Fajr Angle |
| --- | --- | --- |
| 52°N | Birmingham, UK | ~13° |
| 40°N | Ankara, Turkey | ~15° |
| 30°N | Egypt (desert) | ~13.5°-14.5° |
| 27°N | Hail, Saudi Arabia (1020m) | ~14.4° |
| 3°-7°N | Malaysia/Indonesia | ~16°-17° |
| 3°-7°S | Indonesia (Java) | ~16°-17° |
| 33°-37°S | Cape Town / Auckland | ~15°-16° |

This counter-intuitive result (equatorial sites have *higher* angles than mid-latitude sites)
is likely caused by the geometry of the Earth's atmosphere: at equatorial latitudes, the Sun
rises at a steeper angle through the horizon, so morning twilight is briefer and more intense.
The same absolute angle corresponds to a later moment relative to sunrise at lower latitudes.

The ML model should capture this latitude-dependent pattern.