Elastic LIDAR Monitoring of the Night-sky Brightness over Roque de los Muchachos Observatory

Abstract Every large world-class observatory must operate in a very dark environment that is as free possible of anthropogenic sources light pollution, which can degrade the quality ground-based astronomical observations. A LIDAR able to measure, and subtract from its laser return signals, corresponding contribution night-sky brightness. Our elastic system operated semi-continuous mode at night, closely following observation schedule MAGIC Telescopes on Canary island La Palma, Spain. For monitoring brightness, median background rates different atmospheric conditions sky illuminations have been used. In this talk, results data taken with over seven years, March 2013 until 2020, will be presented discussed.