František Xaver Zach
František Xaver Zach known as a baron Franz Xaver von Zach or Ján František Zach (* 4. June 1754, Bratislava – † 2. September 1832, Paris) was a famous astronomer and mathematician born in Slovakia. A small planet 999 Zachia and a crater on the moon are named after him.
He was born on 4th of June 1754 in Bratislava. He studied at the Imperial War Academy in Wienna and after the graduation he recieved the title of a comissioned officer. That was when he left for England to study astronomy. He finished with certificate from the Oxford University. In 1780 he made important astronomical discoveries, he observed the opposition of Mars. In 1785 he joined the Austrian army, he left for England and in 1786 he started to serve Ernest the Second as a lieutenant colonel, where he was supported in his interest in astronomy and he was charged with building an observatory in Goth. Since 1791 he became its director. Scientific publications in astronomy were written in German, Latin and French and after 1788 he published his scientific works in the astronmic journal Allgemeine Geographische Ephemeriden, which was printed in Weimar. During his life in Goth he was mainly focused on the movements of the sun. Results from this research were published in Novae et correctae tabulae motuum solis (New and corrected tables of sun movements), which came out in 1792 in Goth. In 1798 F. X. Zach organised in his observatory the first international astronomical congress. After 1800 he began issuing the monthly magazine with a wide content called Monatliche Correspondenz zur Beförderung der Erd- und Himmelskunde, which he edited until 1827. Zach-directed the observatory in Seeberg near Goth which quickly gained a good name in the scientific world and many world-renowned astronomers went there to make their observations. Zach then lived in Janov for some time and he actively contributed to building of the observatories in the Italien cities Neapol and Lucca. From 1813 he was staying in Switzerland, first he was performing in Geneve, where he established astronomic observatory. From this time especially his gravimetrical researches are important. Then he worked in Elfenaub near Bern and in 1827 he left to Paris, France. His collaboration with a lot of world astronomers such as M. Hell, Jakovlev, Bakunin, Euler and a cartographer Lipsky was enormous. He was named a member of Ugrian Academy of Science in 1832 in memoriam for. Zach died of cholera on 2nd of September in 1832 in Paris.