A new planetarium “ORPHEUS” was developed and introduced at the Pleiades National Planetarium Conference held at St. Louis, MO, USA. The ORPHEUS is for small and midium-sized dome (8m – 16m) and the world’s first planetarium equipped with all the 88 constellations and some other stunning features. The most unique feature is to turn stars on or off according to their brightness. Stars dimmer than magnitude 3.5 can be switched in groups of ½ magnitude each.