Launch of a sounding balloon for horizontal and vertical modelling of ALAN propagation in the atmosphere

Abstract

The propagation of light radiation in the atmosphere is a topic that needs to be properly analyzed to mitigate its negative influence on astronomical observation. This work describes a novel approach for evaluating atmospheric propagation of artificial light at night emphasizing (ALAN) the dependence on altitude and aerosols; it is based on an innovative experiment using a sounding balloon equipped with two sky quality meters (SQM): one vertically pointed at 30○ (SQM-V) and the other horizontally at 90○ (SQM-H) from the zenith. The system was launched during astronomical night condition from an area of the Italian Apennines with low ground light emission and crossed the Tuscan sky, observing the vertical and horizontal ALAN propagation. The data analysis of the two SQMs and their georeferentiation through altitude and trajectory reconstruction allows to model the propagation of light in the experiment field of view from few hundred meters up to an altitude of about 30 km. In this work main focus is given to the tropospheric part of atmosphere up to 12500 meters: the processed data is used to validate a theoretical model taking into account the altitude, the course of the balloon, the atmospheric composition and the population of the cities overflown by the balloon obtaining a correlation of 0.85 with the SQM-H and 0.91 with the SQM-V. The magnitude values close to 21.5 mag arcsec−2 measured by the SQM-V at 2000 meters are an important experimental result for evaluating the influence of the aerosols and the altitude on the ALAN propagation.

Toward a Spectrophotometric Characterization of the Chilean Night Sky. A First Quantitative Assessment of ALAN across the Coquimbo Region

“…Light pollution is today acknowledged as a global problem that, similar to other forms of anthropogenic pollution, has significant impacts on ecosystems and wildlife, causing adverse effects on living organisms (Chepesiuk 2009;Bennie et al 2015;Irwin 2018;Manríquez et al 2019;Svechkina et al 2020). Originally discussed by the professional astronomical community, which was concerned that the inefficient, unnecessary, and uncontrolled use of artificial light at night (hereafter ALAN) could dazzle professional observatories by impeding their vision of the starry sky (Walker 1970;Riegel 1973), nowadays ALAN has become a fertile field for interdisciplinary scientific research (e.g., Maggi & Benedetti-Cecchi 2018;Admiranto et al 2019;Jechow 2019;Cavazzani et al 2020Cavazzani et al , 2022Kolláth et al 2020), socio-economic studies (e.g., Nordhaus 1994;Gallaway et al 2010;Pérez Vega et al 2022), and wide-ranging cultural debates (e.g., Drake 2019; Hamacher et al 2020).…”