It is a convenient system for illumination of dark spaces in contemporary structures and crowded shopping malls high ceilings. The main purpose first is to provide illumination. Since Roof light systems mostly pass large spans profile bodies are designed so that they shall be located to the steel and aluminium bearing construction comfortably. Skylight applications are an aesthetical solution system that solves naturel illumination system in buildings. Onto the main bearing steel construction aluminium profiles are used and a second framework is generated. Into this framework properly scaled glass or opaque materials are adapted. Depending on the passed spans without the existence of the main bearer steel construction aluminium profiles as well shall be made as system solutions. At Roof lights calculations are made according to snow, wind and dynamical loads with the related norms and local regulations and dimensions of profile sections are determined. Rainwater drainage and cleaning system shall be solved. Into the illumination systems smoke flue or ventilation windows can be opened.