c1eeef53c4
Major additions: - Extract all 1,621 Basthoni 2022 SQM records (46 Indonesian sites, Lampiran 2-5) via precomputed_angles.py - Add 9 new raw sighting CSVs: Abdel-Hadi Malaysia, BRIN multistation, Kassim Bahali (2017+2019), Khalifa Saudi, Moonsighting.com, Shaukat 2015 Blackburn UK, Walisongo Sulawesi - Curate aggregate D0 database (115 entries) in research/ Pipeline improvements: - Open-Topo-Data SRTM30m primary elevation API with fallback - APPROVED_RAW_CSVS allowlist prevents circular data ingestion - Pre-computed angle merge path (bypasses back-calculation for SQM data) - BAD_NOTE_MARKERS quality filter for excluded sources Collection tools: - BRIN multistation SQM processors - PDF/HTML table extractor for academic papers - Source tracking database (collection_manifest.json) Documentation: - Rewrite .wiki/Data.md and .wiki/Research.md from scratch - Expand Data-Sources.md with full Basthoni Lampiran breakdown - Add 14 researcher outreach drafts - Update .gitignore to exclude bulk/experimental files |
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| .. | ||
| outreach | ||
| aggregate_comparison.md | ||
| aggregate_d0_values.csv | ||
| birmingham-openfajr.md | ||
| hail-saudi-2018.md | ||
| malaysia-indonesia-2018.md | ||
| nriag-egypt-1984-2014.md | ||
| README.md | ||
| uk-observations.md | ||
Research Archive
This folder contains summaries of academic and institutional research on Islamic twilight
angles. These papers describe other researchers' conclusions about the solar depression angle
at Fajr and Isha. They are useful for understanding the scientific landscape but are not
used as ML training data — only raw per-date observations with explicit timestamps feed
the data/processed/ datasets.
Summary: What the research says
Most peer-reviewed naked-eye studies find Fajr (true dawn / Subh Sadiq) corresponds to a solar depression of roughly 13°–16° depending on site, season, and atmospheric conditions. Isha (Shafaq al-Abyad, white dusk twilight) corresponds to roughly 14°–18°.
The classic convention of 18° Fajr (used by ISNA, MWL, and others) is based on astronomical twilight (the sky becoming fully dark), not the first appearance of dawn light. Observations consistently show true dawn appears while the sun is 12°–15° below the horizon, not 18°.
Papers Summarized
| File | Authors | Year | Site | Finding |
|---|---|---|---|---|
nriag-egypt-1984-2014.md |
Hassan et al. | 1984-2014 | Egypt (6 sites) | 13°-15° Fajr |
nriag-egypt-2022-2025.md |
Rashed et al. | 2018-2025 | Egypt (Fayum, Alex) | 13°-14° Fajr |
hail-saudi-2018.md |
Khalifa | 2014-2015 | Hail, Saudi Arabia | 14° mean Fajr |
malaysia-indonesia-2018.md |
Kassim Bahali | 2017 | KL + Indonesia | 16.67° Fajr |
depok-indonesia-2020.md |
Saksono | 2015 | Depok, Java | ~16° Fajr |
uk-observations.md |
Yusuf, Hizbul Ulama | 1987-2017 | UK (3 sites) | 12°-14° Fajr |
birmingham-openfajr.md |
OpenFajr project | 2016-2026 | Birmingham | 12.5°-14° Fajr |
moonsighting-global.md |
Khalid Shaukat | 2000s | Multiple global | 15°-18° Fajr |