Heliotrope (instrument)

Heliotrope (instrument)

The heliotrope is an instrument that uses a mirror to reflect sunlight over great distances to mark the positions of participants in a land survey. The heliotrope was invented by the German mathematician Carl Friedrich Gauss. [ [http://books.google.com/books?id=s93bifR6Fj0C&pg=RA1-PA358&lpg=RA1-PA358&dq=heliotrope+inventor&source=web&ots=b33mPoQ75X&sig=VctfyuoSbOpp4GrgVETKpl4hLFw&hl=en&sa=X&oi=book_result&resnum=4&ct=result#PRA1-PA358,M1 The Heliotrope, a New Instrument - Arts and Sciences - The Gentleman's Magazine] ] The word "heliotrope" is taken from the Greek: "helios" (Lang-el| Ἥλιος), meaning "sun", and "tropos" (Lang-el|τροπή), meaning "turn". It is a fitting name for an instrument which can be turned to reflect the sun toward a given point.

The heliotrope was utilized by surveyors as a specialized form of target; it was employed during large triangulation surveys where, because of the great distance between stations (usually twenty miles or more), a regular target would appear indistinct. Heliotropes have been used repeatedly as survey targets at ranges of over 100 miles. In California, in 1878, a heliotrope on Mount Saint Helena was surveyed by B.A. Colonna of the USCGS from Mount Shasta, a distance of 192 miles (309km) [ [http://celebrating200years.noaa.gov/theodolites/heliotrope.html NOAA 200th: Collections: Theodolites: heliotrope] ]

The heliotrope was limited to use on sunny days and was further limited (in regions of high temperatures) to mornings and afternoons when atmospheric aberration did not affect the instrument-man's line of sight. The heliotrope operator was called a "heliotroper" or "flasher" and would sometimes employ a second mirror for communicating with the instrument station through heliography, a signalling system using impulsed reflecting surfaces. The inventor of the Heliograph, a similar instrument specialized for signaling, was inspired by observing the use of heliotropes in the survey of India.

References

See also

* Heliograph, a similar instrument, used in communication

External References

* [http://www.amerisurv.com/PDF/TheAmericanSurveyor_BediniHeliotropes_November2004.pdf The Surveyor's Heliotrope]
* [http://books.google.com/books?id=3SEJAAAAIAAJ&pg=RA1-PA569&lpg=RA1-PA569&dq=heliotrope+mirror+surveying&source=web&ots=VrrlXxVead&sig=EU0waoBEpG6iy7xLgDdsl2UtSLs&hl=en Topographic, Trigonometric and Geodetic Surveying, by Herbert Michael Wilson (1912) ] pp. 566-574 are devoted to heliotropes
* [http://books.google.com/books?id=Xv0IAAAAIAAJ Elemente der Vermessungskunde, (in German) by Karl Maximilian von Bauernfeind (1862) ] pp. 115-122 are devoted to Gauss's heliotrope, and the Stierlin and Steinheil heliotropes are described as well.
* [http://www.surveyhistory.org/the_heliotrope1.htm The Heliotrope] A short history.
* [http://transits.mhs.ox.ac.uk/contribute/contrib-results.php?&contributor_id=56&compiled_name=Museum%20Boerhaave&submit=yes Transits of Venus] Page with photographs of three heliotropes from 1873.
* [http://sill-www.army.mil/FAMAG/1969/NOV_1969/NOV_1969_PAGES_73_75.pdf Improvised Heliotrope] this 1969 article also provides the US Army part number for a heliotrope.
* [http://celebrating200years.noaa.gov/theodolites/heliotrope.html Heliotrope] Heliotrope photo, description of 192 mile record.


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Heliotrope — may mean:* Heliotropium , a plant genus * A plant that exhibits heliotropism * Heliotrope (color), a pink purple shade * Heliotrope (instrument), a land surveying instrument *Heliotrope E Zine Speculative Fiction E zine * Heliotrope (mineral),… …   Wikipedia

  • héliotrope — [ eljɔtrɔp ] n. m. • eliotropie 1372; lat. d o. gr. heliotropium « pierre précieuse » et « tournesol » 1 ♦ Plante à feuilles alternes et persistantes, à fleurs odorantes (borraginacées), des régions chaudes et tempérées. L héliotrope d Europe, à… …   Encyclopédie Universelle

  • Heliotrope — He li*o*trope, n. [F. h[ e]liotrope, L. heliotropium, Gr. ?; ? the sun + ? to turn, ? turn. See {Heliacal}, {Trope}.] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line. [1913 Webster]… …   The Collaborative International Dictionary of English

  • Heliotrope purple — Heliotrope He li*o*trope, n. [F. h[ e]liotrope, L. heliotropium, Gr. ?; ? the sun + ? to turn, ? turn. See {Heliacal}, {Trope}.] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line.… …   The Collaborative International Dictionary of English

  • héliotrope — (é li o tro p ) s. m. 1°   Genre de plantes de la famille des borraginées, où l on distingue l héliotrope, heliotropium europaeum, L., dit aussi herbe aux verrues, et l heliotropium peruvianum, L., cultivé pour la beauté et surtout pour la bonne… …   Dictionnaire de la Langue Française d'Émile Littré

  • Heliograph — A Heliograph (from the Greek helios (Lang el| Ἥλιος), meaning sun , and (γραφειν) = write) is a wireless solar telegraph that signals using Morse code flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the …   Wikipedia

  • girasole — Heliotrope He li*o*trope, n. [F. h[ e]liotrope, L. heliotropium, Gr. ?; ? the sun + ? to turn, ? turn. See {Heliacal}, {Trope}.] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line.… …   The Collaborative International Dictionary of English

  • Heliotropium Peruvianum — Heliotrope He li*o*trope, n. [F. h[ e]liotrope, L. heliotropium, Gr. ?; ? the sun + ? to turn, ? turn. See {Heliacal}, {Trope}.] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line.… …   The Collaborative International Dictionary of English

  • turnsole — Heliotrope He li*o*trope, n. [F. h[ e]liotrope, L. heliotropium, Gr. ?; ? the sun + ? to turn, ? turn. See {Heliacal}, {Trope}.] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line.… …   The Collaborative International Dictionary of English

  • heliotrop — HELIOTRÓP, (1, 2) heliotrope, s.n., (3) heliotropi, s.m. 1. s.n. Materie colorantă folosită la vopsitul bumbacului. 2. s.n. Varietate de calcedonie, de culoare verde închis sau roşie cu pete galbene strălucitoare, folosită ca piatră semipreţioasă …   Dicționar Român

Share the article and excerpts

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