Star of the show

摘要

When the Holy Roman Emperor, Friedrick II of Hohenstaufen, returned from the Crusades in the 13th century he had a curious item in his baggage. Made in one of the Islamic courts of the time, it was a dome-shape tent pierced with many holes in the shapes of the constellations of the night sky so a person sitting inside during the day would see the sun shining through the holes. It was mounted on a turntable so at night, the stars would turn above the observer.rnWas it an aid to teaching navigation by the stars? Nobody knows, and the tent is now lost. In any case, what is certain is that it was the first known example of a planetarium.