Michael Kotkamp maintains the UV measurement program at Lauder. He's on the roof of the optic building (complete with safety harness - for OSH!). He is adjusting an instrument that measures sun burning UV radiation. There are several other instruments on the platform that measure various forms of radiation (UV, visible, and infra-red). In the foreground is a solar tracker with instruments to measure direct and diffuse beam radiation and aerosol optical depth.