The current Abruzzo Astronomical Observatory of the National Institute of Astrophysics, with historical headquarters in Teramo, was founded by the Teramo astronomer Vincenzo Cerulli as a private observatory. The Specola di Collurania, as Cerulli named the observatory, became operational in 1893 and was equipped, for the time, with a complete set of instruments. The main instrument was the 40-centimeter Cooke equatorial telescope, the second largest in Italy at the time. With this instrument, Cerulli made, on the occasion of the oppositions of 1894 and 1896, observations of the planet Mars which led him to deny the physical reality of Schiaparelli's canals, interpreting them as optical illusions.
Cerulli was one of the most important Italian astronomers of the early twentieth century, he was president of the Italian Astronomical Society and of the National Astronomical Committee. Engaged in multiple tasks that kept him away from his Observatory, between 1917 and 1919 he donated it to the Italian State in order to preserve its function as an astronomical research center.
The documents from the late 19th century and the first two decades of the 20th century are closely intertwined with those produced by the institutional observatory. They have indeed been found in a single corpus. It is no coincidence that upon Mentore Maggini's death in May 1941, his successor Giovanni Peisino aimed to have a clear understanding of the observatory's assets and was thus compelled to gather numerous documents from previous decades. In fact, Maggini, as a passionate astronomer, had mainly devoted himself to observational activities and scientific discovery.
Consequently, the documents produced in the transition from private observatory to Italian State Observatory (between 1917 and 1919) do not undergo a natural, institutional break between before and after, that is, between Cerulli's observatory and the Observatory.
There are also three small personal collections (Cerulli, Zappa, Maggini) found however separate from the rest of the archive and in any case of a purely scientific nature.