Sky in an umbrella


This umbrella is indeed a small planetarium, in fact it contains a model of the sky as you can see it at night in Boreal Hemisphere; the model reports only principal constellations.
Keeping the top of the umbrella towards The Polar Star, you can simulate the apparent motion of the stars by a rotation of the handle (the stars make an angle of 15 degrees in a hour).
The Professor Zanetti with the umbrella