Evaluation of the night sky quality at El Leoncito and LEO++ in Argentina

Light pollution is a growing concern at many levels, but especially for the astronomical community. Artificial lighting veil celestial objects and disturbs the measurement of night time atmospheric phenomena. This is what motivates our sky brightness measurement experiment in Argentina. Our goal was to determine the quality of two Argentinian observation sites: LEO++ and El Leoncito. Both sites were candidates to host the Cherenkov Telescope Array (CTA). This project consists of an arrangement of many telescopes that can measure high-energy gamma ray emissions via their Cherenkov radiation produced when entering the earth's atmosphere. Even if the two argentinian sites has been excluded from the final CTA site competition, they are still of great interest for other astronomical projects. Especially the El Leoncito site which already hots the CASLEO astronomical complex. In this presentation, we describe the measurement methods used to determine the sky quality. We compared our results with different renowned astronomical sites (Kitt Peak, Arizona, USA, and Mont-Mégantic, Canada). Amongst our results, we found that LEO++ is a high quality site, however there are a lot of aerosols that can interfere with the measurements. El Leoncito shows very low sky brightness levels, which are optimal for low light level detection.

Martin Aubé

AUTHORS/INSTITUTIONS: M. Aubé, N. Fortin, S. Turcotte, Physics, Cégep de Sherbrooke, Sherbrooke, Quebec, CANADAB. García, A. Mancilla, J. Maya, CNEA-CONICET-UNSAM, Instituto de Tecnologas en Deteccion y Astropartculas, Mendoza, ARGENTINA


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