Light pollution evolution around the Cíes Islands

Control and monitoring of light pollution is key to environmental and human wellbeing. To address a proper study of the many factors involved in this research area is mandatory, as well, for particular geographical regions with protected dark skies. ln this context, the worldwide famous Cíes lslands, in the NW Spanish Galician Autonomous Community, hold since 2016 a Starlight Touristic Destination certificate that must be audited every 4 years. Factors as the yearly incoming flux evolution from the nearby town of Vigo, the most populous and densely populated Galician one, versus ageing performance of photometers among other parameters have been carefully evaluated for historical data series starting as early as 2014. A summary of the results obtained, which are not straightforward to interpret, even in some cases ambiguous and lacking a clear explanation, will be here presented and discussed.