Josef Stepling (1716–1778) a určování geografické délky Prahy

Joseph Stepling was interested in determining the longitude of Prague throughout his life. He dedicated to this subject four scientific studies: two at the very beginning of his career, the third some fifteen years later, and the last just two years before his death. The original motivation to engage in this enterprise came from a call issued by the Berlin Academy of Sciences. Attempts to measure the precise longitude of Prague also accompanied the construction of the well-known astronomic tower in the Prague Clementinum, where Stepling carried out important observations of lunar eclipse. In the end, Stepling managed to measure the differences in longitude between Prague, Vienna, and Paris with admirable accuracy. His works on measuring the longitude formed the basis of a tradition which was in late eighteenth and early nineteenth century taken up by astronomers František Gerstner and especially Alois Martin David. This subject was also included in the programme of scientific exploration of Bohemia by the newly formed Royal Bohemian Society of Sciences.