RT Journal Article T1 Monitoring long-term trends in the anthropogenicnight sky brightness A1 Bará, Salvador A1 Lima, Raúl C. A1 Zamorano Calvo, Jaime AB Monitoring long-term trends in the evolution of the anthropogenic night sky brightness is a demanding task due to the high dynamic range of the artificial and natural light emissions and the high variability of the atmospheric conditions that determine the amount of light scattered in the direction of the observer. In this paper, we analyze the use of a statistical indicator, the mFWHM, to assess the night sky brightness changes over periods of time larger than one year. The mFWHM is formally defined as the average value of the recorded magnitudes contained within the full width at half-maximum region of the histogram peak corresponding to the scattering of artificial light under clear skies in the conditions of a moonless astronomical night (sun below −18◦, and moon below −5 ◦ ). We apply this indicator to the measurements acquired by the 14 SQM detectors of the Galician Night Sky Brightness Monitoring Network during the period 2015–2018. Overall, the available data suggest that the zenithal readings in the Sky Quality Meter (SQM) device-specific photometric band tended to increase during this period of time at an average rate of +0.09 magSQM/arcsec2 per year. PB MDPI SN 2071-1050 YR 2019 FD 2019-05-31 LK https://hdl.handle.net/20.500.14352/13593 UL https://hdl.handle.net/20.500.14352/13593 LA eng NO © The autors. Special thanks are given to the executive and technical staff of MeteoGalicia, the Galician Government public meteorological agency, for their efficient management of the Galician Night Sky Brightness Monitoring Network and for the public dissemination of its results. Our warmest memories are for our late colleague Thomas Posch, who developed groundbreaking and extensive research in this field, as well as for Abraham Haim, two recent losses for the light pollution science community. NO Unión Europea. H2020 NO Xunta de Galicia/FEDER NO Foundation for Science and Technology NO FEDER DS Docta Complutense RD 9 abr 2025