transit circle telescope

astronomical instrument
Also known as: meridian circle telescope

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measurement of celestial sphere

  • Keck Observatory
    In telescope: Astronomical transit instruments

    …of transit instruments—for example, the transit circle telescope, the vertical circle telescope, and the horizontal meridian circle telescope. The transit circle determines the right ascension of celestial objects, while the vertical circle measures only their declinations. Transit circles and horizontal meridian circles measure both right ascension and declination at the…

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role of Reichenbach

  • In Georg von Reichenbach

    …German astronomer Friedrich Bessel a transit circle, combining the transit, an instrument used for determining longitude and time, with the mural circle, an instrument mounted on a wall for zenith measurement. This combination had been introduced earlier but had not been adopted. Reichenbach’s form of the instrument came into general…

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time measurement

  • Alfred North Whitehead
    In time: Time determination

    The transit is a small telescope that can be moved only in the plane of the meridian. The observer generates a signal at the instant that the image of the star is seen to cross a very thin cross hair aligned in the meridian plane. The…

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Quick Facts
Born:
Aug. 24, 1772, Durlach, Baden [Germany]
Died:
May 21, 1826, Munich (aged 53)

Georg von Reichenbach (born Aug. 24, 1772, Durlach, Baden [Germany]—died May 21, 1826, Munich) was a German maker of astronomical instruments who introduced the meridian, or transit, circle, a specially designed telescope for measuring both the time when a celestial body is directly over the meridian (the longitude of the instrument) and the angle of the body at meridian passage. By 1796, he was engaged in the construction of a dividing engine, a machine used to mark off equal intervals accurately, usually on precision instruments. In 1804, he was one of the founders of an instrument-making business in Munich, and in 1809, he helped establish at Benediktbeuern an optical works that was later moved to Munich.

In 1819 he built for the German astronomer Friedrich Bessel a transit circle, combining the transit, an instrument used for determining longitude and time, with the mural circle, an instrument mounted on a wall for zenith measurement. This combination had been introduced earlier but had not been adopted. Reichenbach’s form of the instrument came into general use.

This article was most recently revised and updated by Encyclopaedia Britannica.