History
The Astronomical Stations of Cagliari and Carloforte
The historic site of Carloforte
In 1899, the Astronomical Station of Carloforte was established as one of the five locations of the International Latitude Service. Its task was to monitor the variation in latitude of the observation site, used as a parameter for analyzing Earth’s rotation. Its first and historic site was Carloforte, on the island of San Pietro.
Years passed, and by the late ’60s, astronomy entered the University of Cagliari with the creation of the Chair of Astronomy. This marked the beginning of a period of challenging yet continuous growth in the integration between astronomy and Sardinian reality.
The Poggio dei Pini site
In 1978, the next site of the Astronomical Station was created: it was located about 20 km from Cagliari in the area of Poggio dei Pini, in the municipality of Capoterra. More precisely, it occupied about two hectares at the top of Punta sa Menta at about 200 meters above sea level. The choice of this site is closely linked to the historical origins of the Astronomical Station: the site of Punta sa Menta was indeed on the same geographical parallel as the historic site of Carloforte.
In the following twenty years, astronomy in Sardinia was enriched with new stimuli, with the Chair of Astrophysics and the project of the Sardinia Radio Telescope. The commitment to outreach and support for university teaching grew in parallel, with increasing resources and dedication from the staff and facilities of the Astronomical Station.
The merger into INAF and the new Observatory site
In 2002, the Astronomical Station, renamed the Astronomical Observatory of Cagliari, merged with the other eleven Italian Astronomical Observatories into the National Institute for Astrophysics (INAF).
The Poggio dei Pini site remained the Observatory’s location until October 2013, when the entire structure was moved to the former powder magazine in Selargius, in the new premises of the “Campus of Science, Technology, and Environment” of the municipality of Selargius, in the area of Cuccuru Angius. The new site not only significantly reduced travel time from the Observatory to the Sardinia Radio Telescope but is also geographically very close to the University Citadel of Monserrato, allowing for better and more frequent interaction with students and researchers from the University of Cagliari.
Moreover, the new facility is particularly dedicated to scientific outreach and education in the field of astronomy, being equipped with a Teaching Room with observational instruments, an Auditorium that can also be used as a Multimedia Room and Scientific Theater, a Historical Astronomical Museum with instruments used in Carloforte, and a state-of-the-art digital Planetarium.
A hundred years ago
On the day (or rather the night) of October 24, 1899, Giuseppe Ciscato and Emilio Bianchi, astronomers from the Padua Observatory, conducted the first astronomical latitude determinations in Carloforte, the Ligurian-origin town on the island of San Pietro near the southwestern coast of Sardinia. For the observations, they used a Zenith Visual Telescope (VZT) built by the Wanschaff workshops in Berlin and installed on top of the 18th-century San Vittorio tower.
The VZT telescope of Carloforte.
Thus began the activity of the Astronomical Station of Carloforte, which, together with five other stations worldwide, constituted the International Latitude Service (ILS), a network of observatories located on the same geographical parallel (39°08′ N) established by the International Geodetic Association at the General Assembly in Stuttgart (1898) to study in detail the Earth’s rotation through systematic and accurate measurements of latitude variations. Unlike some major European observatories (Paris, Greenwich) founded in the 17th century partly due to the need to solve the longitude determination problem and driven by the maritime supremacy ambitions of the great European powers, the Astronomical Station was instead established to solve a latitude problem and as part of one of those international cooperation projects that were taking their first steps at the end of the last century.
To better understand the causes and reasons that led astronomers and geodesists to undertake this challenging endeavor, it is necessary to consider that the Earth, like other bodies in the solar system and many other objects in the universe, rotates around its axis, and this seemingly simple and natural motion has a series of highly important implications.