This room contains a rich array of instruments designed to measure time: sundials, nocturnals and astrolabes that showed the hour by day or by night.

Without clarifying what time is, astronomy has always striven to define its units on the basis of celestial phenomena, and to develop precise timekeeping instruments.

Displayed here, along with commonly used scientific objects, are highly refined instruments fabricated in the artisans' shops that began to flourish in the 16th century. In the Germanic states, for instance, the members of the Schissler family were renowned, and many of their products entered the Medicean collections. Among the Italian instrument-makers, Giovanni Battista Giusti, Stefano Buonsignori and the Della Volpaia family were outstanding. Especially important in this room are the instruments from the legacy of Viviani, Galileo's last disciple. This collection includes objects of many kinds, revealing Viviani's specific interests in the field of the astronomy.