Struve's name is best known for his observations of double stars, which he carried on for many years. Although double stars had been studied earlier by William Herschel and John Herschel and Sir James South, Struve outdid any previous efforts. He discovered a very large number of double stars and in 1827 published his double star catalogue Catalogus novus stellarum duplicium. Stars of his catalogue are sometimes indicated by the Greek letter sigma, Σ. Thus, 61 Cygni is also designated as Σ2758. Since most double stars are true binary stars rather than mere optical doubles, they orbit around one another's barycenter and slowly change position over the years. Thus Struve made micrometric measurements of 2714 double stars from 1824 to 1837 and published these in his work Stellarum duplicium et multiplicium mensurae micrometricae. Struve carefully measured the "constant of aberration" in 1843. He was also the first to measure the parallax of a star Vega, although Friedrich Bessel had been the first to measure the parallax of a star. In an 1847 work, Etudes d'Astronomie Stellaire: Sur la voie lactee et sur la distance des etoiles fixes, Struve was one of the first astronomers to identify the effects of interstellar extinction. His estimate of the average rate of visual extinction, 1 mag per kpc, is remarkably close to modern estimates. He was also interested in geodetic surveying, and in 1831 published Beschreibung der Breitengradmessung in den Ostseeprovinzen Russlands. He initiated the Struve Geodetic Arc, which was a chain of survey triangulations stretching from Hammerfest in Norway to the Black Sea, through ten countries and over 2,820 km, to establish the exact size and shape of the earth. UNESCO listed the chain on its List of World Heritage Sites in Europe in 2005.
Family
Struve was the second of a dynasty of astronomers through five generations. He was the great-grandfather of Otto Struve and the father ofOtto Wilhelm von Struve. He was also the grandfather of Hermann von Struve, who was Otto Struve's uncle. In 1815 he married Emilie Wall in Altona, who bore 12 children, 8 of which survived early childhood. In addition to Otto Wilhelm von Struve, other children were Heinrich Wilhelm von Struve, a prominent chemist, and Bernhard Wilhelm von Struve, who served as a government official in Siberia and later as governor of Astrakhan and Perm. After his first wife died, he remarried to Johanna Henriette Francisca Bartels, a daughter of the mathematician Martin Bartels, who bore him six more children. The most well-known was Karl de Struve, who served successively as Russian ambassador to Japan, the United States, and the Netherlands. Bernhard's son Pyotr Berngardovich Struve is probably the best known member of the family in mainland Russia. He was one of the first Russian marxists and penned the Manifesto of the Russian Social Democratic Labour Party upon its creation in 1898. Even before the party split into Bolsheviks and Mensheviks, Struve left it for the Constitutional Democratic party, which promoted ideas of liberalism. He represented this party at all the pre-revolutionary State Dumas. After the Russian Revolution, he published several striking articles on its causes and joined the White movement. In the governments of Pyotr Wrangel and Denikin he was one of the ministers. During the following three decades, Pyotr lived in Paris, while his children were prominent in the Russian Orthodox Church Outside of Russia.
