Between 1932 and 1957, at the Specola Tower in Bologna, a new optical technology was invented, one that would revolutionize outer space observatory methods. The tower’s four floors were perforated and a series of hexagonal mirrors were installed side by side at its base, creating a giant telescope of 2 by 24 meters. A mobile camera was set at right angles to the mirrors, with a focal length of 10,41 meters, exposing thousands of glass plates which offered a systematic overview of the city’s zenithal sky. Thirty years of research were necessary for the astronomer Guido Horn D’Arturo to invent the specchio a tasselli – also called multimirror or segmented mirror – an archetype of today’s most advanced telescopes. Full of point-like shapes, these photographic plates are now also full of spots and traces of deteriorated emulsions. This silent film, made by Giuseppe Spina, is composed of digital scans and blow-ups of Horn D’Arturo’s plates.