A dioptra (sometimes also named dioptre or diopter, from Greek: διόπτρα) is a classical astronomical and surveying instrument, dating from the 3rd century BC. The dioptra was a sighting tube or, alternatively, a rod with a sight at both ends, attached to a stand. If fitted with protractors, it could be used to measure angles.
Graphic reconstruction of the dioptra, by Venturi, in 1814. (An incorrect interpretation of Heron's description)
It continued in use as an effective surveying tool. Adapted to surveying, the dioptra is similar to the theodolite, or surveyor's transit, which dates to the sixteenth century. It is a more accurate version of the groma.
There is some speculation that it may have been used to build the Eupalinian aqueduct. Called "one of the greatest engineering achievements of ancient times," it is a tunnel 1,036 meters (4,000 ft) long, "excavated through Mount Kastro on the Greek island of Samos, in the 6th century BCE" during the reign of Polycrates. Scholars disagree, however, whether the dioptra was available that early.[1]
An entire book about the construction and surveying usage of the dioptra is credited to Hero of Alexandria (also known as Heron; a brief description of the book is available online; see Lahanas link, below). Hero was "one of history’s most ingenious engineers and applied mathematicians."
The dioptra was used extensively on aqueduct building projects. Screw turns on several different parts of the instrument made it easy to calibrate for very precise measurements
The dioptra was replaced as a surveying instrument by the theodolite.
^Apostol, Tom M. "The Tunnel of Samos" (PDF). caltech.edu. Retrieved 19 June 2011.
Further reading
Isaac Moreno Gallo (2006) The Dioptra Tesis and reconstructon of the Dioptra.
Michael Jonathan Taunton Lewis (2001), Surveying Instruments of Greece and Rome, Cambridge University Press, ISBN0-521-79297-5
Lucio Russo (2004), The Forgotten Revolution: How Science Was Born in 300 BC and Why It Had To Be Reborn, Berlin: Springer. ISBN3-540-20396-6.
Evans, J., (1998) The History and Practice of Ancient Astronomy, pages 34–35. Oxford University Press.
External links
Michael Lahanas,
Nathan Sidoli (2005), Heron's Dioptra 35 and Analemma Methods: An Astronomical Determination of the Distance between Two Cities, Centaurus, 47(3), 236-258
dioptra, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, december, 2021, le. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Dioptra news newspapers books scholar JSTOR December 2021 Learn how and when to remove this template message This article is about a surveying instrument For other uses see dioptra disambiguation A dioptra sometimes also named dioptre or diopter from Greek dioptra is a classical astronomical and surveying instrument dating from the 3rd century BC The dioptra was a sighting tube or alternatively a rod with a sight at both ends attached to a stand If fitted with protractors it could be used to measure angles Graphic reconstruction of the dioptra by Venturi in 1814 An incorrect interpretation of Heron s description Contents 1 Use 2 See also 3 References 4 Further reading 5 External linksUse EditGreek astronomers used the dioptra to measure the positions of stars both Euclid and Geminus refer to the dioptra in their astronomical works It continued in use as an effective surveying tool Adapted to surveying the dioptra is similar to the theodolite or surveyor s transit which dates to the sixteenth century It is a more accurate version of the groma There is some speculation that it may have been used to build the Eupalinian aqueduct Called one of the greatest engineering achievements of ancient times it is a tunnel 1 036 meters 4 000 ft long excavated through Mount Kastro on the Greek island of Samos in the 6th century BCE during the reign of Polycrates Scholars disagree however whether the dioptra was available that early 1 An entire book about the construction and surveying usage of the dioptra is credited to Hero of Alexandria also known as Heron a brief description of the book is available online see Lahanas link below Hero was one of history s most ingenious engineers and applied mathematicians The dioptra was used extensively on aqueduct building projects Screw turns on several different parts of the instrument made it easy to calibrate for very precise measurementsThe dioptra was replaced as a surveying instrument by the theodolite See also EditAlidadeReferences Edit Apostol Tom M The Tunnel of Samos PDF caltech edu Retrieved 19 June 2011 Further reading EditIsaac Moreno Gallo 2006 The Dioptra Tesis and reconstructon of the Dioptra Michael Jonathan Taunton Lewis 2001 Surveying Instruments of Greece and Rome Cambridge University Press ISBN 0 521 79297 5 Lucio Russo 2004 The Forgotten Revolution How Science Was Born in 300 BC and Why It Had To Be Reborn Berlin Springer ISBN 3 540 20396 6 Evans J 1998 The History and Practice of Ancient Astronomy pages 34 35 Oxford University Press External links EditMichael Lahanas Heron of Alexandria Inventions Biography Science Nathan Sidoli 2005 Heron s Dioptra 35 and Analemma Methods An Astronomical Determination of the Distance between Two Cities Centaurus 47 3 236 258 Bamber Gascoigne History of Measurement historyworld net Tom M Apostol 2004 The Tunnel of Samos Engineering and Science 64 4 30 40 Portals Astronomy Stars Geography Greece Solar System Retrieved from https en wikipedia org w index php title Dioptra amp oldid 1127506234, wikipedia, wiki, book, books, library,
