At Bologna’s Specola Tower, 1932–1957, an optical technology was invented which would revolutionize astronomy. The tower’s four floors were perforated and a series of hexagonal mirrors was installed at its base, creating a giant telescope of 2×24 meters. A mobile camera was set at right angles to the mirrors and thousands of glass plates where exposed which offered a systematic overview of the city’s zenithal sky. Thirty years of research... see more