ИСТИНА

Used technique for search for optical flashes on the Moon is suitable for detection of even faint flashes caused by 0.1 kg high-speed meteoroids. The intensity of Na D2 line during quiet period on February 3-6, 2014 was significantly lower than that during maximum of the Perseid 2009 meteor shower. This observed fact can be interpreted that during activity of main meteor showers meteoroid bombardment is the main source of exospheric Na atoms at the poles of the Moon. Additional simultaneous spectral observations of the lunar exosphere and search for optical flashes are required during activity of main meteor showers such as Geminids, Quadrantids, and Perseids.