The Kraus-type

radio telescope A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency ...

design was created by Dr.

John D. Kraus John Daniel Kraus (June 28, 1910 – July 18, 2004) was an American physicist known for his contributions to electromagnetics, radio astronomy, and antenna theory. His inventions included the helical antenna, the corner reflector antenna, a ...

(1910–2004). Kraus-type telescopes are

transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1979 film), a 1979 Israeli film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 ...

instruments, where the flat

primary mirror A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope. Description The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal ...

reflects radio waves towards the

spherical A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ce ...

secondary mirror A secondary mirror (or secondary) is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary. Secondary mirro ...

, which focuses it towards a mobile focal carriage. The primary tilts north–south to select any object near the

meridian Meridian or a meridian line (from Latin ''meridies'' via Old French ''meridiane'', meaning “midday”) may refer to Science * Meridian (astronomy), imaginary circle in a plane perpendicular to the planes of the celestial equator and horizon * ...

, while the focal carriage moves east–west along

railroad Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

ties to track objects near transit.

Examples

The Nançay radio telescope in France and the former Big Ear in Ohio are Kraus-type telescopes, and the southern section of the

RATAN-600 The RATAN-600 (russian: РАТАН-600 – радиоастрономический телескоп Академии наук – 600, an acronym for the " Academy of Sciences Radio Telescope – 600") is a radio telescope in Zelenchukskaya, ...

ring in Russia can operate as a Kraus-type telescope. Radio telescopes {{Astronomy-stub