Evolution of Brightness and Color of the Night Sky in Madrid

José Robles,Jesús Gallego,Kevin J Gaston,Sergio Pascual,Alejandro Sánchez De Miguel,Jaime Zamorano

doi:10.3390/rs13081511

José Robles, Jesús Gallego + Show 4 more

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https://doi.org/10.3390/rs13081511

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Abstract

Major schemes to replace other streetlight technologies with Light-Emitting Diode (LED) lamps are being undertaken across much of the world. This is predicted to have important consequences for nighttime sky brightness and color. Here, we report the results of a long-term study of these characteristics focused on the skies above Madrid. The sky brightness and color monitoring station at Universidad Complutense de Madrid (inside the city) collected Johnson B, V, and R sky brightness data, Sky Quality Meter (SQM), and Telescope Encoder Sky Sensor-WiFi (TESS-W) broadband photometry throughout the night, every night between 2010–2020. Our analysis includes a data filtering process that can be used with other similar sky brightness monitoring data. Major changes in sky brightness and color took place during 2015–2016, when a sizable fraction of the streetlamps in Madrid changed from High-Pressure Sodium (HPS) to LEDs. The sky brightness detected in the Johnson B band darkened by 14% from 2011 to 2015 and brightened by 32% from 2015 to 2019.

Highlights

Departamento de Física de la Tierra y Astrofísica, Facultad CC
We see that the 2019 night specFigure we present a graph comparing theThe mean night sky spectra midnight trum In shows the4, blue bump of the Light-Emitting Diode (LED)
We see that the band responses show how the changes in spectra are related to the change in the night sky’s spectrum shows the blue bump of the LED spectrum

Summary

Introduction

Departamento de Física de la Tierra y Astrofísica, Facultad CC. Físicas, Universidad Complutense de Madrid, Instituto de Física de Partículas y del Cosmos, IPARCOS, 28040 Madrid, Spain. Artificial lighting is, for example, often excessively bright, and is allowed to spread into areas (spatial trespass) and times (temporal trespass) beyond those in which it is needed This has a wide array of consequences for living organisms, including measurable effects on human health [2,3] and on wild plants and animals [2,3,4], many of which arise from the impacts of artificial nighttime lighting on the timings of biological activities [5]. Given these environmental impacts, it is important to understand the effects of widespread and ongoing street lighting changes from legacy

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