Animations (only parts in nuclei in the film) and images, many of them archival and foreign, illustrate that the notion of time is associated with movement and its measurement is performed by the rotation of the Earth around its axis and the Sun. The angle of inclination of the Earth in this last movement also marks the climatic seasons. From the need for greater accuracy in measuring time, gnomons and solar quadrants arose, for whose reading the duodecimal numbering is used. Based on this numbering, time zones and mechanical measuring devices were established, illustrated by the clock mechanism with a church bell. The evolution of astronomy determines the creation of more accurate electronic devices for the evaluation of time, such as the meridian telescope, the Markowitz chamber, the electronic oscillators and the telescope, with which astronomers work at the National Observatory.