This armillary sphere is a didactic model of the heliocentric solar system, which illustrates the movements of the Earth as it revolves around the Sun and rotates on its own axis.
The two vertical circles, the equinox and solstice markers, are fixed to the lathe-turned wooden base; to this are fixed the horizontal ecliptic circle and band showing the months and constellations of the zodiac. A pin fixed to the vertical circle functions as the axis of rotation of four circles that indicate the movements around the Sun of Saturn, Jupiter and Mars, each represented on its respective ring by a gold disc. The golden globe in the centre representing the Sun is surrounded by the small rings of Mercury and Venus. The Earth’s movement is achieved by means of two pulleys and a transmission cord: when the Earth is made to revolve around the Sun, the rope and pulleys cause it to rotate on its axis.
Built by L.C. Desnos, Paris.
Restored in 2017 by Paolo Brenni and Anna Giatti in the Fondazione Scienza e Tecnica laboratory in Florence.
Device on display.