Light Pollution Mapping and Its Implications for Astronomical Observatories
Year: 2025
Type: conference-paper
Abstract: This study evaluates a decade-long evolution of artificial night-sky brightness in major Philippine astronomical observatories by integrating VIIRS-DNB radiance trends, Sen’s slope non-parametric change detection, temporal inflection-point analysis, and spatial light-pollution classification using the Falchi et al. (2016) global framework. Results reveal a clear divergence between urban and rural observatories: urban sites particularly those in Metro Manila and Quezon City exhibit statistically significant positive Sen’s slopes, indicating persistent and accelerating increases in radiance from 2014 to 2024. These increases are accompanied by multiple inflection points that reflect episodic surges from infrastructure growth, LED retrofits, and expanding commercial zones. Conversely, rural observatories in Cavite and Romblon display stable or minimally increasing radiance, confirming the buffering effect of geographic isolation. However, elevated radiance growth in Baguio suggests encroaching peri-urban skyglow even in historically favorable high-altitude environments. Light-pollution maps reinforce these temporal trends: urban regions transition from highly polluted to extreme, while rural sites remain in low pollution categories. Collectively, the findings demonstrate that Philippine night-sky quality is undergoing rapid degradation in urban centers, leaving only a few viable dark-sky locations for scientific astronomical research. The study underscores the urgent need for national dark-sky policy, strategic observatory relocation, and the implementation of lighting regulations to safeguard remaining observational capacity.
Institution: Rizal Technological University
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7165522015