The Satel-Light Internet server provides to designers and engineers daylight information which was previously unavailable. It is based on a database of daylight and solar radiation, covering Western and Central Europe, which was produced as part of a European project called SATELLIGHT. This database has been computed from the images produced by the Meteosat satellite. Thus it has an excellent spatial resolution (every 5 km on average) and an excellent temporal resolution (every 30 mn).