Балтық немісі астрономы Отто Вильгельм Струве

Baltic German astronomer

Otto Wilhelm von Struve (May 7, 1819 (Julian calendar: April 25) – April 14, 1905) was a Russian astronomer of Baltic German origins. In Russian, his name is normally given as Otto Vasil'evich Struve (Отто Васильевич Струве). Together with his father, Friedrich Georg Wilhelm von Struve, Otto Wilhelm von Struve is considered a prominent 19th century astronomer who headed the Pulkovo Observatory between 1862 and 1889 and was a leading member of the Russian Academy of Sciences.

Struve was born in 1819 in Dorpat (Tartu), then Russian Empire, as the third son out of eighteen sons and daughters of Friedrich Georg Wilhelm von Struve and Emilie Wall (1796–1834). He graduated from a Dorpat gymnasium at the age of 15 and was one year too young by the university rules. Yet, he was admitted to the Imperial University of Dorpat as a listener and completed the program by the age of 20. While studying, he was assisting his father at the Dorpat Observatory. In 1839, he graduated from the university and moved to the newly opened Pulkovo Observatory, where he was immediately appointed as assistant of the director (his father). For his initial observations, he was given the degree of Master of Astronomy by the University of St. Petersburg in 1841. In 1842, he visited Lipetsk for observations of the solar eclipse and in 1843 defended his PhD. In 1843 Otto formally became a Russian subject.

During 1843 and 1844, Struve participated in longitude measurements between Altona, Greenwich and Pulkovo, which were based on large displacement of chronometers over the Earth surface. This newly developed method was adopted in Russia, and from 1844, the longitude was measured starting not from the Tartu Observatory but from the Pulkovo Observatory. Much of the 1844 Struve dedicated to studying the Sun. He deduced its apex coordinates and linear velocity as 7.3 km/s. Although it was significantly smaller than the correct value of 19.5 km/s measured in 1901, Struve's result was correct in that the velocity of the Sun was smaller than that of stars. and OΣΣ in his appendix. Struve continued his father's work in several directions. In particular, they compiled famous Pulkovo catalogues of stellar coordinates, including several thousands double stars observed with a 15 inch refractor. Between 1816 and 1852, the observatory completed the famous survey triangulation measurements of the angular arc (named Struve Geodetic Arc). The measurements extended through over 2,820 km, from Hammerfest in Norway to the Staraya Nekrasovka village by the Black Sea, and aimed to establish the exact size and shape of the Earth. In 1851, while observing a solar eclipse, he concluded that the solar corona and protuberances are physically connected with the Sun rather than being simply an optical effect, as most astronomers then believed. Later in 1860 he suggested a close connection between solar protuberances and flares. Struve also observed satellites of Uranus (Ariel and Umbriel, in 1851) and of Neptune. He also measured the rings of Saturn and discovered (in parallel with other researchers) the dark inner ring of Saturn. In 1861, in his report to the Academy of Sciences, he had supported and developed the ideas of William Herschel that stars are formed from the diffuse matter. In 1872, Struve organized assistance with equipment to the newly opened observatory in Tashkent – a southern location offering clear skies for observations. In 1874, he prepared several expeditions to monitor the transit of Venus across the solar disk in eastern Asia, Caucasus, Persia and Egypt. In 1887, he sent several groups within Russia to observe the solar eclipse. In some of those expeditions, he took part personally. Struve remained a top authority at the Russian Academy and his requests, e. g. regarding staff appointments were always granted. The first refusal, in 1887, disappointed Struve so much that he applied for resignation and was stopped from that only by the Tsar Alexander III, who requested Struve to keep his posts until the 50th anniversary of the Pulkovo Observatory in 1889. and it was a part of long term Russia US astronomy partnership during the 19th century. Within that collaboration, many American astronomers stayed at Pulkovo for observations and exchanged data with Russian scientists by mail. By the initiative of Struve, two US astronomers, Simon Newcomb and Asaph Hall were appointed as Foreign Members of the Russian Academy of Sciences. He was a member of the Royal Swedish Academy of Sciences. Between 1852 and 1889, he was also a member of the Russian Academy of Sciences and became an academician in 1856. In 1874 he became foreign member of the Royal Netherlands Academy of Arts and Sciences. The asteroid 768 Struveana was named in honor of Otto Wilhelm, Friedrich Georg Wilhelm and Karl Hermann Struve; and a lunar crater was named for another 3 astronomers of the Struve family: Friedrich Georg Wilhelm, Otto Wilhelm and Otto. The Struve Geodetic Arc was included to the World Heritage List in 2005.