The founding of Arcetri Observatory in Florence

Abstract

The first idea of establishing a public astronomical observatory in Florence, Capital of the Grand Duchy of Tuscany, dates to the mid of the 18th century. Initially, the use of a low building on a high ground was proposed, and the hill of Arcetri suggested as a proper location. At the end of the century, the Florence Observatory - or Specola - was built instead on a tower at the same level as the city's centre. As soon as astronomers started to use this observatory, they recognized all its flaws and struggled to search for a better location. Giovanni Battista Donati, director of the Specola of Florence from the eve of the Italian Unification in 1859, finally succeeded in creating a new observatory: first, he obtained funds from the Parliament of the Kingdom of Italy to build an equatorial mount for the Amici 28-cm refractor, which could not be installed conveniently in the tower of the Specola; then, he went through the process of selecting a proper site, seeking funds and finally building Arcetri Observatory. Although Donati was a pioneer of spectroscopy and astrophysics, his intent was to establish a modern observatory for classical astronomy, as the Italian peninsula did not have a national observatory like those located in many foreign capitals - Florence was the capital of the Kingdom of Italy from 1865 to 1871. To promote the project, Donati made use of writings by one of the most authoritative European astronomers, Otto Wilhelm Struve. The paper describes all these steps, eventually leading to the final inauguration of the Arcetri Observatory in 1872, almost 150 years ago.