The Kraus-type radio telescope

Radio telescope

A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...

 design was created by Dr. John D. Kraus (1910–2004).

Kraus-type telescopes are transit

Transit

-Transportation:* Ford Transit, a van made by the Ford Motor Company* Mass transit, public transport systems in which passengers are carried in large numbers* Navigational transit, when a navigator observes two fixed reference points in line...

 instruments, where the flat primary

Primary mirror

A primary mirror is the principal light-gathering surface of a reflecting telescope.-Description:The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal , or in later telescopes, glass or other material coated with a reflective layer...

 reflects radio light towards the spherical secondary

Secondary mirror

A secondary mirror 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 mirrors in the form of an optically flat diagonal mirror are used to...

, which focuses it towards a mobile focal carriage. The primary tilts North-South to select any object near the meridian

Meridian (astronomy)

This article is about the astronomical concept. For other uses of the word, see Meridian.In the sky, a meridian is an imaginary great circle on the celestial sphere. It passes through the north point on the horizon, through the celestial pole, up to the zenith, through the south point on the...

, while the focal carriage moves East-West along railroad ties to track objects near transit.

The following telescopes are Kraus-type.

• Nançay Decimetric Radio Telescope
• The Big Ear
  The Big Ear
  The Ohio State University Radio Observatory was a Kraus-type radio telescope located on the grounds of the Perkins Observatory at Ohio Wesleyan University from 1963 to 1998. Known as "Big Ear", the observatory was part of The Ohio State University's Search for Extraterrestrial Intelligence project...