Il progetto di telescopio a tasselli di Guido Horn d’Arturo: forefather of the new generation multi-mirror telescopes

In this thesis we want to acknowledge one of the topics developed in his vast work by Guido Horn d’Arturo, the Director of the Bologna University Astronomical Observatory for large part of the 20th century. The topic addressed is of great international relevance in astronomy, even if it is unknown to most researchers. This thesis wants to be an in-depth analysis of the work started in 1999 for the inauguration of the new location of the Department of Astronomy and, mostly, the dedication of the Library to Guido Horn d’Arturo. A booklet printed in that occasion collects the most important papers on the instrument that the astronomer first conceived and realised: a telescope with a tessellated mirror. Thanks to the donation of Horn’s private correspondence to the Department Historical Archives, done by the Horn’s descendant, it has been possible to reconstruct the history, the evolution of the project, the efforts and the experiments that have led to the realization of the tessellated telescope, an attempt to obtain a patent included. This project occupied a great part of his life. The astronomer’s activities came to a standstill owing to historical events. Being Horn a Jew, he was obliged to leave his high position at Bologna University because of racial laws. He could resume his office at University and continue to work hard on his telescope only at the end of World War II. He continued to work on his project developing it more and more. In 1978, Luigi Jacchia - a Horn’s pupil and friend, then at the Smithsonian Astrophysical Observatory - was the first to call attention to the link between the project of Horn’s tessellated mirror and the then under construction Multiple Mirror Telescope in his paper “Forefathers of the MMT”. In conclusion, with this thesis we would like to enhance and spread the ingenious work done by this astronomer who succeeded in overcoming the large number of scientific, technical, economic, and environmental difficulties of his time.