The Vienna University Observatory conserves one of the most important collections of historically significant science books reaching from the 15th to the 18th century. Especially within the Central European countries no astronomical library with a comparable, historically grown inventory exists.
The first Vienna University Observatory was founded in 1755 and Jesuit Maximilian Hell (1720-1792) was nominated as its first director. Therefore the inventory of the Astronomy Library, as well as the inventory of the Vienna University Library, mainly arose from the Jesuit's collections. The Institute of Astronomy Library contains 5 books older than 1500, 56 printed before 1600 and a total of 500 books prior to 1800 - which is the content of the Rare Book Collection and this project.