Johann Zahn

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Johann Zahn (also Joanne Zahn ; born March 29, 1641 in Karlstadt ; † June 27, 1707 ) was a German Premonstratensian chorister , philosopher , optician , inventor , mathematician and author of various works.

life and work

Johann (or Johannes) Zahn was a student of Caspar Schott in Würzburg . His main field of work was optics including astronomical observation. Zahn described himself as a student of the astronomer Franz Griendel von Ach from Nuremberg . He was a professor of mathematics at the University of Würzburg . He was also a canon in the Premonstratensian monastery of Oberzell and from 1685 until his death in 1707 provost in the monastery of Unterzell .

Goethe's portable camera obscura

Zahn is best known for his research in the field of optics . He further developed the single-lens reflex camera with an upright image (deflecting mirror) developed by Johann Sturm in 1676 by placing a telescopic lens consisting of two parts (convex and concave) with different focal lengths one behind the other, so that a larger image was created ( reflex camera obscura ). He also painted the exposure chamber black to avoid reflections. Except for the shutter system, the invention represents the prototype of a photo camera. In 1686 he constructed a portable camera obscura. A mirror mounted inside the camera at an angle of 45 degrees to the lens projected the image upwards onto a screen, where it could be easily drawn. The image could be brought into focus through a rectangular extract. Johann Wolfgang von Goethe also used a device of the same design on his travels.

His work Specula physico - mathematico - historica notabilium was a summary of all natural sciences . The book Oculus artificialis teledioptricus sive telescopium was the standard work in the field of optics at the time . When the second edition appeared in 1702, Zahn surprised his readers with extensive additions that made his book indispensable for every scholar and instrument maker. Zahn's compendium begins with the theory of optics, then it continues with the optical instruments, which include microscopes, telescopes, mirrors and lenses. Now Zahn brought up the difficult subject of glass selection and grinding before ending with descriptions of astronomical observations.

Fonts

Specula physico-mathematico-historica
Oculus artificialialis teledioptricus
  • Specula physico-mathematico-historica notabilium ac mirabilium sive Mundi mirabilis in two parts (I: 448 pages; II: 460 pages), Nuremberg: Knorz 1696.
  • Oculus artificialis teledioptricus sive telescopium, ex abditis rerum naturalium & artificialium principiis explicatum ac e 'triplici fundamento, physico seu naturali, mathematico dioptrico et machanicoo, seu practito stabilitum . [3 vol.]. Würzburg: Quirinus Heyl (1685–86).

photos

Images in Specula physico - mathematico - historica notabilium :

literature

Web links

Commons : Johann Zahn  - Collection of Images

Individual evidence

  1. ^ Otto Volk : Mathematics, astronomy and physics in the past of the University of Würzburg. In: Peter Baumgart (Ed.): Four hundred years of the University of Würzburg. A commemorative publication. Degener & Co. (Gerhard Gessner), Neustadt an der Aisch 1982 (= sources and contributions to the history of the University of Würzburg. Volume 6), ISBN 3-7686-9062-8 , pp. 751–785; here: p. 757 f.
  2. ↑ Ralf Kern: Scientific instruments in their time. Volume 1: Striving for Accuracy in Time and Space, p. 202.
personal data
SURNAME Zahn, Johann
BRIEF DESCRIPTION German Premonstratensian canon, philosopher, optician, inventor, mathematician and author
DATE OF BIRTH March 29, 1641
PLACE OF BIRTH Karlstadt
DATE OF DEATH June 27, 1707