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Add 6 new data collection pipelines and their processed outputs: Sources added: - TESS/Stars4All photometer network: 37 months (Jun 2017-Aug 2020), ~40k raw events from 100+ European stations via Zenodo archives - Globe at Night citizen science: 26k twilight observations (2006-2024), filtered from 308k total observations for solar depression 6-22 deg - GaN-MN continuous monitoring: 45 months (Jan 2022-Sep 2025), ~12.5k twilight events from 88 stations across 20+ countries - Galicia SQM network: 14 stations, 1-min resolution, 7.5k events - Madrid/Majadahonda SQM: multi-year continuous monitoring, 3.1k events - washetdonker.nl Netherlands: 7 stations, 3.3k morning events - Academic papers: Jordan (Abed 2015), Fayum Egypt, India photometer Pipeline changes: - ingest.py: add all new files to APPROVED_RAW_CSVS allowlist, fix filter to use allowlist instead of hardcoded exclusions - .gitignore: exclude bulk raw data directories (BSRN, TESS, GaN-MN, washetdonker, Globe at Night downloads) Final dataset: 56,668 Fajr + 34,763 Isha = 91,431 total records Previous: 5,871 Fajr + 46 Isha = 5,917 total records
60 lines
3.5 KiB
Markdown
60 lines
3.5 KiB
Markdown
# Alteration of Twilight Sky Brightness Profile by Light Pollution
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**Authors:** Muhamad Syazwan Faid, Mohd Zambri Zainuddin, Nazri Muslim, Nor Hazmin Sabri, Zainol Abidin Ibrahim, Chong Hun Yih
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**Year:** 2024
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**Journal:** Scientific Reports, 14: 26237
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**DOI:** 10.1038/s41598-024-76550-3
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**PMID:** 39496720, **PMCID:** PMC11535048
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**URL:** https://www.nature.com/articles/s41598-024-76550-3
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**Sites studied:** 12 sites across Malaysia (urban/suburban/pristine) + 1 in Australia
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**Observation method:** SQM (Sky Quality Meter)
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**Date range:** 2008-2022 (84 total observations, 72 validated)
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**Mean angle (Fajr):** Pristine: -17.49 deg, Suburban: -15.67 deg, Urban: -11.50 deg (brightness stability onset)
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## Sites
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| # | Location | Coordinates | Classification | Zenith mag/arcsec2 |
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|---|----------|-------------|----------------|-------------------|
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| 1 | Putrajaya | 2 54'N, 101 41'E | Urban | 17.11 |
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| 2 | Teluk Kemang | 2 27'N, 101 51'E | Rural | 19.5 |
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| 3 | Tanjung Balau | 1 48'N, 104 24'E | Rural | 19.78 |
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| 4 | Pantai Masjid Tengku Zaharah | 5 24'N, 103 57'E | Rural | 19.85 |
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| 5 | Pantai Batu Buruk | 5 19'N, 103 9'E | Rural | 19.23 |
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| 6 | Coonabarabran, Australia | 31 15'S, 149 16'E | Pristine | 21.59 |
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| 7 | Pantai Mek Mas | 6 19'N, 102 9'E | Pristine | 21.3 |
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| 8 | Balai Cerap Unisza | 5 24'N, 102 35'E | Pristine | 20.08 |
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| 9 | Pulau Bunting | 5 51'N, 100 20'E | Pristine | 18.94 (rejected) |
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| 10 | Simpang Mengayau, Sabah | 7 12'N, 116 30'E | Pristine | 21.64 |
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| 11 | Pantai Melawi Bachok | 5 24'N, 102 35'E | Pristine | - |
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| 12 | Pantai Nenasi | 3 36'N, 103 30'E | Pristine | - (rejected) |
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## Summary
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A large-scale SQM study comparing twilight brightness profiles across urban, suburban, and pristine sites in Malaysia and Australia. 84 twilight SQM datasets collected from 2014-2022, with 72 validated (12 rejected: 2 sites with inconsistent data).
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The key finding: light pollution shifts the "brightness stability point" (the solar depression angle at which twilight brightness becomes indistinguishable from the full-night baseline) dramatically:
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- Pristine: -17.49 degrees (close to the classical 18 deg)
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- Suburban: -15.67 degrees (shifted inward by ~2 deg)
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- Urban: -11.50 degrees (shifted inward by ~6 deg!)
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This means in heavily light-polluted areas, the SQM cannot detect dawn until the sun is much closer to the horizon, because the urban sky glow already exceeds the natural twilight brightness.
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Teluk Kemang long-term data (2008-2016) shows progressive brightening correlating with population growth, with full-night brightness changing from 19.69 to 19.55 mag/arcsec2 over 8 years.
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## Data Availability
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**AGGREGATE ONLY.** The paper reports:
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- Mean brightness stability parameters per classification (Table 3)
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- Full-night zenith brightness per site (Table 2)
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- Teluk Kemang historical trend (Table 4)
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- NO per-night dates or individual SQM time series
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The 72 validated data points are summarized as profiles, not individual observations. No supplementary data files with raw per-night data were published.
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## For ML Training
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This paper is primarily useful for understanding how light pollution affects apparent dawn angle. The aggregate brightness stability values can serve as calibration points:
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- Pristine sites: dawn detection at ~17.5 deg (useful as SQM benchmark)
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- The per-site zenith brightness values help classify observation quality
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Cannot extract per-night training rows. Already partially covered by abdelhadi_2022_malaysia_sqm.csv in our dataset (same research group, overlapping sites).
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