MEASUREMENTS OF NIGHTTIME ATMOSPHERIC OPTICAL DEPTH PRELIMINARY DATA FROM A MOUNTAIN SITE IN SOUTHERN ITALY

A grating spectrometer equipped with a photomultiplier was used to mea sure atmospheric optical depth with the moon as an extraterrestrial li ght source. Measurements are presented in the window regions in the sp ectral range 0.32-0.64 mu m, with a resolution of about 3 nm. The Lang ley method was applied to estimate atmospheric optical depth. Measurem ents have been performed at a mountain site in southern Italy, at 1247 m above sea level in the context of the Gamma-ray Air-Cherenkov Multi Telescope experiment. (C) 1998 Elsevier Science Ltd. All rights reser ved.