Yrjö Väisälä

Yrjö Väisälä [ Yrjö Väisälä ] ( born September 6, 1891 in Kontiolahti, Finland, † July 21, 1971 in Rymättylä, Finland) was a Finnish Geodetic, astronomer and physicist.

He was (now part of Joensuu ) born as the seventh of eight children of John Weisell, employee of a sawmill in Utra, and Emma Bridget Jääskeläinen. The father died in 1904, and the mother, who in 1906 assumed the Finnish spelling of the family name, the five still minor children moved on alone. Nevertheless, the three youngest, Vilho, Yrjö and Kalle, attend university and pursue an academic career.

Väisälä obtained his PhD degree in 1922 and worked during this time as a surveyor and astronomer until 1925 at the Geodetic Institute of the University of Turku. He worked here with the triangulation and developed the concept of light interference for length measurement on larger distances. According to him, the Väisälä interference comparator was named for the measurement of normal routes. In 1925 he became professor of physics.

In his further career Yrjö Väisälä shifted his activity to meteorology and astronomy. He transferred the method of triangulation to astronomical objects. Väisälä one of the founders of the Astronomical Observatory of the University of Turku in 1952 and was its director until his death.

In the course of his scientific work, he discovered 128 asteroids and two comets. The lunar crater Väisälä was named after him because of his merits, as well as the asteroid ( 1573) and Väisälä ( 2804 ) Yrjö.

Discovered asteroid

Writings (selection )

• The application of the light interference to length measurements on larger distances, Academic Bookstore, Helsinki 1923
• Application of light interference at baseline measurements, Valtineuv. Kirjap, Helsinki 1930
• Remarks on the method of the base measurement using the light interference, Academic Bookstore, Helsinki 1955
• With Liisi Oterma: Application of astronomical triangulation, Suomen geodeettisen laitos, Helsinki 1960