page_title: Pedro Nunes
section_title: Inventions
hierarchical_section_title: Pedro Nunes / Work / Inventions
caption_attribution_description: Italiano: Unico nonio esistente in versione originale di Pedro Nuñez English: Original nonius Português: O único nónio existente
context_page_description: Pedro Nunes was a Portuguese mathematician, cosmographer, and professor, from a New Christian family.
  Considered one of the greatest mathematicians of his time, Nunes is best known for his contributions to the nautical sciences, which he approached, for the first time, in a mathematical way. He was the first to propose the idea of a loxodrome, and was the inventor of several measuring devices, including the nonius, named after his Latin surname.
context_section_description: Nunes worked on several practical nautical problems concerning course correction as well as attempting to develop more accurate devices to determine a ship's position.
  He created the nonius to improve the astrolabe's accuracy.  This consisted of a number of concentric circles traced on the astrolabe and dividing each successive one with one fewer divisions than the adjacent outer circle.  Thus the outermost quadrant would comprise 90° in 90 equal divisions, the next inner would have 89 divisions, the next 88 and so on.  When an angle was measured, the circle and the division on which the alidade fell was noted.  A table was then consulted to provide the exact measure.
  The nonius was used by Tycho Brahe, who considered it too complex. The method inspired improved systems by Christopher Clavius and Jacob Curtius.  These were eventually improved further by Pierre Vernier in 1631, which reduced the nonius to the Vernier scale that includes two scales, one of them fixed and the other movable. Vernier himself used to say that his invention was a perfected nonius and for a long time it was known as the “nonius”, even in France. In some languages, the Vernier scale is still named after Nunes, for example nonieskala in Swedish.
  Pedro Nunes also worked on some mechanics problems, from a mathematical point of view.
caption: Nunes nonius original model
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