Grades 1 and up. The "sun" shines onto the nine planets as they orbit around it. The central tower and planetary support rods are black so that they "disappear" in a darkened room for a spectacular effect! Replace the solar dome with the star dome include to create a spectacular planetarium sky complete with major constellation names. In addition the base features a special 1000-hour light bulb and planetary longitude marks so the planets can be set up to their correct positions. The Solar System model is powered either by four C batteries (not included) or by an optional AC adapter (not included).