Transit instrument

Transit instrument

In astronomy, transit instruments are used for the precise observation of star positions. The instruments can be divided into three groups:

Meridian instruments

for observation of star transits in the exact direction of South or North:
* Meridian circles, Mural quadrants etc.
* Passage instruments (transportable, also for prime vertical transits)

Universal instruments

which allow transit measurements in "anyone" direction
* Astronomical theodolites
* Altaz telescopes with graduated eyepieces (also for satellite transits)
* Kine theodolites

Zenith instruments and Astrolabes

* Zenith telescope
* Photozenith tube (PZT)
* zenith cameras
* Danjon astrolabe, Zeiss Ni2 astrolabe, Circumzenital

Observation techniques and accuracy

Depending on the type of instrument, the measurements are carried out
* visually and manual time registration (stopwatch, Auge-Ohr-Methode, chronograph)
* visually by impersonal micrometer (moving thread with automatic registration)
* photographic registration
* CCD or other electro optic sensors.

The accuracy reaches from 0.2" (theodolites, small astrolabes) to 0.01" (modern meridian circles, Danjon). Early instruments (like the mural quadrants of Tycho Brahe) had "no telescope" and were limited to about 0.01°.

See also

* Astronomical transit
* Position astronomy, Astrogeodesy
* latitude/longitude observation, vertical deflection

External links

* Karl Ramsayer: "Geodätische Astronomie", Vol.2a of "Handbuch der Vermessungskunde", 900 p., J.B.Metzler, Stuttgart 1969
* Cauvenet and Brünnow's Handbooks of "Spherical Geodesy"
* [http://www.encyclopedia.com/doc/1E1-transinst.html "Transit instrument" in the Encyclopedia.com]
* [http://www.1911encyclopedia.org/Transit_Circle Transit circle technique (Classic Encyclopedia)]
* [http://content.cdlib.org/ark:/13030/ft6f59p0v8/?layout=metadata&brand=calisphere Great Transit at Lick Observatory, +Photo]
* [http://www.jostjahn.de/roboterteleskop/ Modern roboter telescopes]
* [http://www.ast.cam.ac.uk/~dwe/SRF/camc.html The Carlsberg Automatic Meridian Circle]
* [http://www.arm.ac.uk/history/instruments/Jones-transit.html Photo of a 19 century Transit Instrument (Jones 1826)]
* [http://links.jstor.org/sici?sici=0370-1662(1866%2F1867)15%3C385%3AOATAAZ%3E2.0.CO%3B2-Q Transit instruments udes by the Survey of India, 1867)]
* [http://www.transitinstruments.com/ Transit instruments, Inc.]


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Look at other dictionaries:

  • Transit instrument — Transit Trans it, n. [L. transitus, from transire to go over: cf. F. transit. See {Transient}.] 1. The act of passing; passage through or over. [1913 Webster] In France you are now . . . in the transit from one form of government to another.… …   The Collaborative International Dictionary of English

  • transit instrument — n. 1. a telescope mounted at right angles to a horizontal east west axis so that it can be rotated only in the vertical plane of the meridian at its site: used to observe and time the transit of celestial bodies across the meridian 2. TRANSIT… …   English World dictionary

  • transit instrument — noun a telescope mounted on an axis running east and west and used to time the transit of a celestial body across the meridian • Hypernyms: ↑telescope, ↑scope * * * noun 1. : a telescope that is mounted at right angles to a horizontal east west… …   Useful english dictionary

  • transit instrument — 1. Astron. See meridian circle. 2. Survey. transit (def. 6a). [1805 15] * * * …   Universalium

  • Prime-vertical transit instrument — Prime Prime, a. [F., fr. L. primus first, a superl. corresponding to the compar. prior former. See {Prior}, a., {Foremost}, {Former}, and cf. {Prim}, a., {Primary}, {Prince}.] 1. First in order of time; original; primeval; primitive; primary.… …   The Collaborative International Dictionary of English

  • Transit — Trans it, n. [L. transitus, from transire to go over: cf. F. transit. See {Transient}.] 1. The act of passing; passage through or over. [1913 Webster] In France you are now . . . in the transit from one form of government to another. Burke. [1913 …   The Collaborative International Dictionary of English

  • Transit circle — Transit Trans it, n. [L. transitus, from transire to go over: cf. F. transit. See {Transient}.] 1. The act of passing; passage through or over. [1913 Webster] In France you are now . . . in the transit from one form of government to another.… …   The Collaborative International Dictionary of English

  • Transit compass — Transit Trans it, n. [L. transitus, from transire to go over: cf. F. transit. See {Transient}.] 1. The act of passing; passage through or over. [1913 Webster] In France you are now . . . in the transit from one form of government to another.… …   The Collaborative International Dictionary of English

  • transit compass — Transit Trans it, n. [L. transitus, from transire to go over: cf. F. transit. See {Transient}.] 1. The act of passing; passage through or over. [1913 Webster] In France you are now . . . in the transit from one form of government to another.… …   The Collaborative International Dictionary of English

  • Transit duty — Transit Trans it, n. [L. transitus, from transire to go over: cf. F. transit. See {Transient}.] 1. The act of passing; passage through or over. [1913 Webster] In France you are now . . . in the transit from one form of government to another.… …   The Collaborative International Dictionary of English

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