To: bosscha@itb.ac.id
Subject: Request for Per-Night Twilight Observation Data — Open-Source Prayer Time Research

Assalamu alaykum wa rahmatullahi wa barakatuh,

My name is Ali Camarata. I am an independent researcher building an open-source dataset of verified Fajr and Isha twilight observations for data-driven Islamic prayer time calculation.

I have been studying the excellent work of Prof. Dani Herdiwijaya and colleagues at Bosscha Observatory, including:
- Herdiwijaya (2016), J. Phys.: Conf. Ser. 771, 012033 (5 Indonesian stations)
- Herdiwijaya (2020), J. Phys.: Conf. Ser. 1523, 012007 (multi-station comparison)
- Herdiwijaya (2015), ICOPIA proceedings (Bosscha, Bandung, Cimahi, Yogyakarta, Amfoang)

These papers report aggregate mean depression angles across hundreds of observation nights, but the per-night data (specific dates with specific observed Fajr/Isha times) would be far more valuable for building predictive models.

Would it be possible to obtain the raw per-night observation logs from any of Bosscha's twilight monitoring campaigns? Even a subset of the data (e.g., the 136 clear nights from the Yogyakarta 2014-2016 campaign, or the Kupang Amfoang measurements) would be a significant contribution.

The data I need for each observation night:
- Calendar date
- Local observed time of Fajr onset (morning twilight detection)
- Local observed time of Isha onset (evening twilight disappearance), if recorded
- Any sky condition notes

Our project: https://github.com/acamarata/pray-calc-ml
Current dataset: 4,200+ verified observations from 140+ sites across 20+ countries.

I would be pleased to share our compiled dataset and acknowledge Bosscha Observatory's contribution in all publications.

Jazakallahu khairan,
Ali Camarata
alisalaah@gmail.com