The library of the Vatican Observatory
When it was originally founded in 1891, the Vatican Observatory was located in the same building as the Vatican Library and had access to its resources. In 1910, Fr. Hagen, then director of the Vatican Observatory, took on the task of ordering and enriching the library of the Vatican Observatory. The collection of magazines and journals was expanded through purchases and donations from various authors and observatories; and with the approval of Pope Pius X, the ancient treasures of the Vatican Library that were of astronomical interest were transferred to the Vatican Observatory. Among these were the complete series of the publications Comptes Rendus of Paris (beginning in 16XX) and Philosophical Transactions of London (from its first volume in 1665).
Since then, the collection of books and scientific journals has been growing thanks to donations, acquisitions, and more transfers from the Vatican Library, with the most recent publications in astronomy, physics, and philosophy of sciences. Most current journals are available in electronic format.
Today the library of the Vatican Observatory contains more than 22,000 volumes. Along with current research it possesses a valuable collection of rare antique books including works of Copernicus, Galileo, Newton, Kepler, Brahe, Clavius, and Secchi.