LIDAR

The LIDAR is a single-wavelength elastic Rayleigh LIDAR operating at 532 nm wavelength, which is close enough to 300 nm where the Cherenkov spectrum peaks. A LIDAR inversion algorithm has been developed to obtain a vertical profile of the total extinction coefficient due to the presence of clouds and aerosols. Typically the LIDAR will track the current position of the MAGIC telescopes and performs 25000 laser shots every 5 minutes. A single laser run can take 30 to 60 seconds. The laser is fired along the optical axis of the LIDAR telescope, the light is reflected and scattered by molecules (Rayleigh scattering) and particles (Aerosol/Mie scattering) in the atmosphere, and from the arrival time and the intesity of the return, the optical transmission at several heights (3, 6, 9, 12km) is calculated. If a cloud is present, its height and thickness can be measured. The transmission and cloud height values are only updated if the LIDAR is operational. close