Schmidt , Bernhard Voldemar
(1879–1935) Estonian telescope maker
Schmidt, who was born on the island of Naissaar, in Estonia, received little education. After working in Gothenburg, Sweden, he went in 1901 to study engineering at Mittweida in Germany, near Jena. He set up his own workshop in 1904 in Mittweida and manufactured high-grade mirrors to be used in telescopes. He also built some reflecting telescopes, including one for the Potsdam Astrophysical Observatory, and set up his own observatory. In 1926 he moved to the Hamburg Observatory in Bergedorf. As a master craftsman he worked unaided even though he had lost his right arm as a boy. He was also an alcoholic and claimed to have his best ideas after prolonged drinking bouts. He died in a mental hospital.
His name is known to all astronomers as the designer of one of the most basic items of observatory equipment, the Schmidt telescope. This was built to overcome some of the penalties inherent in the design of the large parabolic reflectors like the Mount Wilson 100-inch (2.5-m) telescope. Parabolic mirrors are used rather than spherical ones in telescopes to correct the optical defect known as spherical aberration and thus allow the light from an object to be accurately and sharply focused. This accurate focusing only occurs, however, for light falling on the center of a parabolic mirror. Light falling at some distance from the center is not correctly focused owing to a different optical distortion in the image, known as coma.
This limits the use of parabolic reflectors to a narrow field of view and thus precludes them from survey work and the construction of star maps. Schmidt replaced the primary parabolic mirror with a spherical mirror, which though coma-free did however suffer from spherical aberration, thus preventing the formation of a sharp image. To overcome this fault Schmidt introduced a ‘corrector plate’ through which the light passed before reaching the spherical mirror. It was so shaped to be thickest in the center and least thick between its edges and the center. In this way a comparatively wide beam of light passing through it is refracted in such a way as to just compensate for the aberration produced by the mirror and produce an overall sharp image on a (curved) photographic plate.
Schmidt's first hybrid reflector/refractor was ready and installed in the Hamburg Observatory in the early 1930s. Observatories have since used the Schmidt telescope to photograph large areas of the sky. The whole sky has now been surveyed with these instruments and the results, which include the very faintest objects down to a magnitude of 21, are published in the Palomar Sky Survey and the Southern Sky Survey.

Scientists. . 2011.

Look at other dictionaries:

  • Schmidt, Bernhard Voldemar — ▪ German optician born March 30, 1879, Naissaar, Estonia died December 1, 1935, Hamburg, Germany       optical (optics) instrument maker who invented the telescope (Schmidt telescope) named for him, an instrument widely used to photograph large… …   Universalium

  • Bernhard Voldemar Schmidt — Bernhard Schmidt (* 30. März 1879 auf der zu Estland gehörigen Insel Naissaar (auch als Insel Nargen bekannt); † 1. Dezember 1935 in Hamburg) war ein auf astronomische Optik spezialisierter Optiker. Nach ihm ist das Schmidt Teleskop benannt, das… …   Deutsch Wikipedia

  • Schmidt telescope — a wide angle reflecting telescope used primarily for astronomical photography, in which spherical aberration and coma are reduced to a minimum by means of a spherical mirror with a corrector plate near its focus. Also called Schmidt reflector.… …   Universalium

  • Schmidt — type of astronomical telescope lens used for photography, 1939, from Estonian born German optician Bernhard Voldemar Schmidt (1879 1935), who invented it …   Etymology dictionary

  • Schmidt — Schmịdt,   1) Alfred, Philosoph und Soziologe, * Berlin 19. 5. 1931; seit 1972 Professor in Frankfurt am Main; Schmidt gehört der Frankfurter Schule der kritischen Theorie an (Mitherausgeber der Gesammelten Schriften M. Horkheimers, Übersetzer… …   Universal-Lexikon

  • telescope — /tel euh skohp /, n., adj., v., telescoped, telescoping. n. 1. an optical instrument for making distant objects appear larger and therefore nearer. One of the two principal forms (refracting telescope) consists essentially of an objective lens… …   Universalium

  • nebula — nebular, adj. /neb yeuh leuh/, n., pl. nebulae / lee , luy /, nebulas. 1. Astron. a. Also called diffuse nebula. a cloud of interstellar gas and dust. Cf. dark nebula, emission nebula, reflection nebula …   Universalium

  • АСТРОНОМЫ — Барнард, Эдуард Эмерсон (Barnard, Edward Emerson) (1857 1923), американский астроном, открыл звезду с наибольшим собственным движением (звезда Барнарда), обнаружил пятый спутник Юпитера, зафиксировал 16 комет. Широко известен его фотографический… …   Энциклопедия Кольера

  • List of Estonians — This is a list of notable Estonians Architects *Tõnu Altosaar (born 1945) (Canada) *Andres Alver (born 1953) *Dmitri Bruns (born 1929) *Karl Burman (1882–1965) *Eugen Habermann (1884–1944) *Georg Hellat (1870–1943) *Otto Pius Hippius (1826–1883)… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”