This research is studying the possibility of improving natural lightining inside king Hussien mosque, that is depending mainly on artificial lighting despite the fact that Jordan is enjoying with 300 sunny days with more than 600000 lux of the direct sun and in considering that the sky illuminance is measured to be more than 10000 lux in 90% of the whole year. Passive sunportal system refers to technology used to improve naturallighting, include outside mirrors, inside lenses, pipes and other similar devices. These devices have been studied by many researchers, while our study uses a scale model of sunportal system which is applied in the prayer hall in AlHussien mosque as a case study. The research will base on three stages, descriptive stage will review the literature about natural lighting and mosque, analytical stage will analyze passive system units, especially Sun Portal system, and applied stage will analyze the measurements of natural lighting before and after adding the passive units. Based on the analysis of the data received from the three stages, the experiment revealed significant findings including that the illuminance of the mosque raised up to400 lux by using passive sunportal system, the initial reading is promising and improves the quality and quantity of lighting inside the mosque.
