VLT site test Cerro Paranal

The site for the very large telescope was carefully chosen on the basis of astroclimatology data. Astroclimatology is the study of weather conditions for astronomical observations. In addition to the usual cloud and wind, other parameters are also considered, such as seeing (the atmospheric turbulence) and the water vapour content. This shows the equipment of the astroclimatology group during site test at Cerro Paranal in Chile, in 1989.