Ignazio Porro

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Ignazio Porro

Ignazio Porro (born November 25, 1801 in Pinerolo , † October 8, 1875 in Milan ) was an Italian engineer and inventor of the Porro prism named after him , which is used in binoculars and stereo microscopes . The Porro Bluff , a cliff in the Antarctic , is named after him .

Military time

Ignazio Porro was the son of a lieutenant engineer in the Italian army. Ignazio also joined the Italian army as an artillery cadet. Even during his military service, he worked in land surveying and made numerous improvements to geodetic systems. Since 1839 he called his optical systems for land surveying as " tacheometers " and defined the term tachymetry . In 1842 he retired from military service with the rank of major in the reserve.

Workshops in Turin and Paris

Cross section through a Porro prism binocular

As a civilian, Porro set up a workshop in Turin . Five years later he moved to Paris and founded the “Institut technomatique” there. There he constructed an asymmetrical camera lens system in 1847 that improved the image quality at the edge of the image. In the early 1850s, he recommended the use of telephoto lenses for shooting distant subjects.

In 1854 Porro received the patent for his most famous invention, reversing and redirecting, with the patent specification “Certain applications of total or normal reflection of light on transparent surfaces alone or in conjunction with refraction” in France and England.

Based on the Porro prisms, Porro developed the monocular binoculars, the "Longue Vue Cornets". The “Lunette Napoleon III” was developed as a further type of binoculars of this type and was personally presented to Emperor Napoleon III on February 22, 1855 . presented.

Teaching in Florence and Milan

In 1861 he returned to Italy and taught tachymetry in Florence . The Technical College in Milan appointed him professor of surveying ( geodesy ) in 1863 . In the same year Porro founded the company "Tecnomasio italiano" and two years later in Milan the "Filotecnica". Until his death he was unable to derive any significant economic benefit from his numerous inventions. Scientific recognition was also denied to him during his lifetime and after his death. When Ernst Abbe wanted to patent an optical inversion system himself in 1893, he was surprised to find that Porro, which he had never heard of before, was decades ahead of him.

literature

  • Albert König, Horst Köhler: The telescopes and range finders . 3rd edition, 1959
  • Rolf Riekher: Telescopes and their masters, Berlin, 2nd edition 1990
  • Emil-Heinz Schmitz: Manual for the history of optics. Tape. 4, Part A, The Step into the XX Century. Supplementary volume 1: The telescope. Bonn: 1982.

Web links

Commons : Ignazio Porro  - collection of images, videos and audio files

Individual evidence

  1. ↑ Patent GB195402377 : Certain applications of total or partial reflection of light on transparent surfaces either alone or combined with the reflection. Published on November 9, 1854 (currently not available on Espace). ‌
personal data
SURNAME Porro, Ignazio
ALTERNATIVE NAMES Porro, Paolo Ignazio Pietro; Porro, Ignatio
BRIEF DESCRIPTION Italian engineer
DATE OF BIRTH November 25, 1801
PLACE OF BIRTH Pinerolo
DATE OF DEATH October 8, 1875
Place of death Milan