The Historical Archive of the Arcetri Astrophysical Observatory: Antonio and Giorgio Abetti Archive

In 1993, during the renovation of the library, we found boxes containing letters, reports, papers, scientific notes, circulars, conference proceedings, astronomical data collections, books, maps, invoices, balance sheets, obituaries, pictures and spectrograms, drawings and journal cuttings. The archival material spanned the years from 1893 to the early 1970s. However, for the time being, only Giorgio Abetti’s correspondences are being considered (about 2300 items). In addition, a complete bibliography of Antonio and Giorgio Abetti’s publications have been prepared so it is possible to complete the reconstruction of both personalities. 1. Antonio and Giorgio Abetti Antonio and Giorgio Abetti were directors of the Arcetri Astrophysical Observatory from 1895 to 1925 and from 1925 to 1954 respectively; and, they left their indelible mark on Italian astronomical research. Antonio Abetti’s specialty was positional astronomy and he observed minor planets, comets, stellar occultations and partial solar eclipses. In 1874, he participated in the Italian expedition directed by Pietro Tacchini in Muddapur, Bengala, in order to observe the transit of Venus on the solar disk. He built astronomical instruments such as the Amici equatorial and the small Bamberg meridian, but, above all, he gave new life to the Arcetri Observatory following the death of Wilhelm E. Tempel, an amateur astronomer and an excellent lithographer, who was Director of the observatory from 1875 to 1889. From the onset, the scientific activities of Giorgio Abetti were noted for being unusual. His international collaborations were established with George E. Hale in 1908 and their friendship lasted a life time. In 1913, G. Abetti took part, as a geodetic and geophysical astronomer, in the De Filippi expedition in Karakorum, Himalaya and Turkestan. 326 The Historical Archive of the Arcetri Astrophysical Observatory 327 Since 1921, Giorgio Abetti initiated the idea of constructing a solar tower on the Arcetri hillside. Thanks to the scientific and financial help of Hale, in 1923 the solar tower began construction, and in 1925, the same year of his appointment as Director of the Arcetri Astrophysical Observatory, the solar tower was officially completed. In 1929, Giorgio Abetti was the author of the section of the Handbuch der Astrophysik on solar physics. He held many national and international academic positions and during his long life he never stopped being interested in solar and non solar (planetary and galactic physics) research. Figure 1. The construction of the Arcetri Astrophysical Observatory (1872)