Dark and Quiet Skies for Science and Society. Report and recommendations
From 5 to 9 October 2020, around 1,000 people participated in the Dark and Quiet Skies for Science and Society Workshop, which resulted in this report and recommendations for local governments to preserve dark and calm skies. The report addresses three classes of interference: Artificial Light At Night (ALAN), radio wavelength emission and Low Earth Orbit (LEO) satellite trails. Incorporating suggestions from participants in the workshop, the report has been prepared by more than 85 experts organised across five Working Groups. The Working Groups focused on, respectively: Dark Sky Oases, Optical Astronomy, Bioenvironment, Satellite Constellations and Radio Astronomy. Each Working Group has made recommendations for steps that can be taken to mitigate the particular effects of the human activities they focused on. Since many of these activities also have important benefits, such as increased safety thanks to urban illumination and network connectivity provided by satellites, care has been taken to recommend actions that reduce their negative impacts without compromising their effectiveness for their original purposes. This is essential for the quick development and implementation of actions to preserve dark and quiet skies, for both scientific exploration and cultural heritage.