Ludwig Struve - Research

Research

A few years after retirement of his father, in 1894, Gustav moved to the University of Kharkiv. There, in 1897 he became professor in astronomy and geodesy and director of the observatory. Prior to Struve, the Kharkiv Observatory was not registered within the Russian leveling network and the altitude of Kharkiv was based on rather inaccurate trigonometric leveling conducted by local triangulation. It took Struve five years of hard work to include the observatory to the Russian leveling network. In 1912, he was elected as Dean of the Physics and Mathematics Department of Kharkiv University. In 1914, he founded a workshop of fine mechanics at the department and headed it for five years. Prior to that, such institutions were inexistent in Russia, and foreign engineers were personally invited for precision mechanical work. Struve attempted to build a national school in this area, but with limited success. He himself was a skilled engineer and constructed an instrument for the measurement of "an individual error using artificial star.” This device was invented by H. G. van de Sande Bakhuyzen at the Leiden Observatory and was actively used by Struve.

Struve's research was first focused on celestial mechanics, in particular precession and other motion within the Solar System. It then expanded on the study of the positions and motion of stars, in particular single and double stars lying within the angular range of the Tartu Observatory. He used occultation of stars by the Moon to refine the value of the lunar radius. He also determined the apex coordinates of the Sun's movement and was one of the first astronomers to estimate, in 1887, the rotation rate of the Milky Way.

On the basis of his observations in Kharkiv, Struve compiled a catalogue "Observation of 779 zodiac stars” (1898–1902). Between 1908 and 1915, Struve with collaborators determined right ascension and declination of 1407 circumpolar stars, taking about 11,000 observations for each coordinate. The results were published in the "Kharkiv differential catalogue of declination of 1407 circumpolar stars in FK4 system for mean epoch of 1911 year" and "The results of a comparison of the catalogue of declination of 1407 circumpolar stars and the Fabritius catalogue with the tables of proper motion of 412 circumpolar stars".