After studying physics and mathematics at the Czech Charles-Ferdinand University and 12 years of teaching in České Budějovice, Otto Seydl reached his desired profession in astronomy. Thanks to the support of astronomer František Nušl, who spent most of his time in the Ondřejov observatory, Seydl was able to join the observatory in Prague`s Clementinum in 1921. Seydl was responsible for the administration and management of the library, took care of the regular time service, participated in meteorological observations and until 1927 in magnetic measurements. After defending his dissertation on stellar statistics under the title The Classification of Fixed Stars of 6.5 Magnitude and Brighter from the Harvard Revised Photometry Catalogue in the Galactic Coordinate System, Seydl became a Doctor of Science. The topic of stellar statistics continued to interest Seydl in the following years and he published several other papers on it. In 1930 he began to organize the Clementinum archive, which dates back to 1775. This activity awakened in Seydl a passion for the history of astronomy, which did not leave him for the rest of his life. Seydl was interested in the personalities who worked at the Clementinum Observatory - his works on Antonín Strnad and Alois Martin David were particularly inspiring. However, he also worked on the history of clocks and instruments or published an inventory of auroras observed in Bohemia and Moravia between 1013 and 1951. With incredible diligence, Otto Seydl searched for hard-to-find information in monastery archives and libraries across the country, and in order to understand historical astronomical writings, he began to learn Arabic and cuneiform. After František Nušl retired, Seydl became the administrator of the State Observatory in 1938. During the Nazi occupation he was deprived of his post (he was allowed to continue working at the observatory), but after World War II he became its director in 1947. In 1948, however, he was ordered to retire and had to leave both the Clementinum and Ondřejov. Seydl continued his work on the history of astronomy and published many papers. He was more intensively involved in meteorology during this period and worked at the Hydrometeorological Institute in Prague from 1955 to 1958. Otto Seydl died on 15 February 1959 in Prague.
The commemorative plaque to Otto Seydl is in the vestibule of the Josef Hlávka Primary School in Přeštice. It was installed on the initiative of the Czech Astronomical Society on 22 September 2017.
Hyklová, P.: Dědictví klementinských exaktních věd a druhý život „matematického muzea“ v 19. a 20. století. In: Acta Universitatis Carolinae – Historia Universitatis Carolinae Pragensis. 2/2017, s. 45–65.
Internetové zdroje:
Boháček, J.: Otto Seydl (1884–1859). In: Akademický bulletin. Oficiální časopis Akademie věd ČR. URL: http://abicko.avcr.cz/miranda2/m2/2009/05/13/ [24.8.2021].
Jíra, J.: Odhalení pamětní desky Otty Seydla. In: Česká astronomická společnost. Astronomický informační server astro.cz. URL: https://www.astro.cz/clanky/osobnosti/odhaleni-pametni-desky-otty-seydla.html [24.8.2021].