The development of astronomy in Naples: the tale of two large telescopes made by William Herschel

Abstract

Mirrors and telescopes produced by William Herschel were popular in Europe, due to the opportunities they offered for deep sky observations. Leading public and private observatories acquired them to observe new objects in the Solar System, such as planets and asteroids, and strange stellar structures, stellar nebulae and clusters. After the establishment of the Chair of Astronomy at the University of Naples, it took thirty-four years before an observatory was built. Due to the commitment of Lord Acton, Naples became the first Italian city to host a telescope made by William Herschel. A few years later, Count von Hahn also bought a Herschel telescope for his private observatory in Germany, and at the time this was the largest telescope made by Herschel in mainland Europe. In this paper we recount the remarkable story of these telescopes by way of the scientific activities of the two astronomers who were associated with them, and how von Hahn's telescope eventually also ended up in Naples.