The apparatus includes a light concentrating structure with a transparent medium which deflects direct and diffuse light. The light emanates from a defined region of the sky, e.g. southern direction, by total reflection to a zone considerably smaller than the light entry zone. The zone is wholly or partially mirrored and the light which is not totally reflected is used to illuminate a room behind the glazed aperture. ADVANTAGE - Shades from direct sunlight whilst maintaining transparency for diffuse daylight.