Osservatorio Astronomico G.D. Cassini

Perinaldo's municipal observatory honours Giovanni Domenico Cassini, the seventeenth-century astronomer born in the village. Its roof-mounted dome houses a 380 mm Newtonian telescope. The Cassini Division in Saturn's rings bears his name.

Why it matters

Perinaldo is a ridge-top commune above the flower coast and the birthplace of astronomer Giovanni Domenico Cassini in 1625. Cassini's career took him from the meridian of San Petronio in Bologna to the founding generation of the Paris Observatory. In 1989 the commune established an observatory inside the town hall, linking Cassini's legacy with astronomical research and education.

What to notice

The observatory's principal instrument is a Newtonian reflector with a 380 mm mirror and 1700 mm focal length, housed in a dome built onto the municipal palace. Displays connect Cassini's work to the meridian line he traced in Bologna's Basilica of San Petronio, his move to Paris in 1669, the 1672 measurement of the Earth–Sun distance using observations from Cayenne, and his discoveries concerning Saturn's satellites and rings.

Context and history

Cassini studied in Genoa before taking a post in Bologna, where his meridian in San Petronio became a reference for calendar reform. From 1669 he worked in Paris for the Académie des Sciences, helped develop the royal observatory and contributed to the first scientific topographic map of France. The municipal observatory in Perinaldo was established in 1989 through the work of the administration and the Cassini astronomy circle of Sanremo. A 2020 restyling renewed the observatory's scientific and educational setting.