The Effelsberg 100-m Radio Telescope is a

radio telescope A radio telescope is a specialized antenna (radio), 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 r ...

in the

Ahr Hills The Ahr HillsElkins, T.H. (1972). ''Germany'' (3rd ed.). London: Chatto & Windus, 1972. . ( or ''Ahreifel'' ) are a range of low mountains and hills up to and long in the Eifel region of Germany, which lie roughly southwest of Bonn on the borde ...

(part of the

Eifel The Eifel (; , ) is a low mountain range in western Germany, eastern Belgium and northern Luxembourg. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the southern area of the German-speaking Com ...

) in

Bad Münstereifel Bad Münstereifel () is a historical spa town in the district of Euskirchen (district), Euskirchen, Germany, with about 17,000 inhabitants, situated in the far southwest of the German state of North Rhine-Westphalia. The little town is one of on ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

. Inaugurated in 1972, for 29 years the Effelsberg Radio Telescope was the largest fully steerable radio telescope on Earth, surpassing the

Lovell Telescope The Lovell Telescope ( ) is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire, in the north-west of England. When construction was finished in 1957, the telescope was the largest steerable dish radio telescope in the world a ...

in the UK. In 2000, it was surpassed by the

Green Bank Observatory The Green Bank Observatory (previously National Radio Astronomy Observatory, Green Bank) is an Observatory, astronomical observatory located in the United States National Radio Quiet Zone, National Radio Quiet Zone in Green Bank, West Virginia, G ...

's Robert C. Byrd Green Bank Telescope in Green Bank, US, which has a slightly larger elliptical 100 by 110-metre aperture.

Geography

The telescope is located about 1.3 km northeast of Effelsberg, a southeastern part of the town of

North Rhine-Westphalia North Rhine-Westphalia or North-Rhine/Westphalia, commonly shortened to NRW, is a States of Germany, state () in Old states of Germany, Western Germany. With more than 18 million inhabitants, it is the List of German states by population, most ...

. It is less than 300 m west of the 398 m high Hünerberg, which is in neighbouring

Rhineland-Palatinate Rhineland-Palatinate ( , ; ; ; ) is a western state of Germany. It covers and has about 4.05 million residents. It is the ninth largest and sixth most populous of the sixteen states. Mainz is the capital and largest city. Other cities are ...

. The boundary is a stream, the Effelsberger Bach, which runs only a few metres east of the telescope. The Effelsberger Bach is 6.5 km long, flowing from the Effelsberger Wald into the Sahrbach, which in turn flows south and into the

Ahr Ahr () is a river in Germany, a left tributary of the Rhine. Its source is at an elevation of approximately above sea level in Blankenheim in the Eifel, in the cellar of a timber-frame house near the castle of Blankenheim. After it crosses f ...

river. A hiking path leads past the telescope; in 2004 part of this was turned into a planet trail with information panels about the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

with its

planets A planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets by the most restrictive definition of the te ...

. The trail ends at the 39 cm model of the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

next to the visitor centre.

Radio telescope

The Effelsberg radio telescope is operated by the

Max Planck Institute for Radio Astronomy The Max Planck Institute for Radio Astronomy (MPIfRA) (German: ''Max-Planck-Institut für Radioastronomie'') is located in Bonn, Germany. It is one of 80 institutes in the Max Planck Society (German: Max-Planck-Gesellschaft). History By com ...

Bonn Bonn () is a federal city in the German state of North Rhine-Westphalia, located on the banks of the Rhine. With a population exceeding 300,000, it lies about south-southeast of Cologne, in the southernmost part of the Rhine-Ruhr region. This ...

, the

radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...

institute of the

Max-Planck-Gesellschaft The Max Planck Society for the Advancement of Science (; abbreviated MPG) is a formally independent non-governmental and non-profit association of German research institutes. Founded in 1911 as the Kaiser Wilhelm Society, it was renamed to the M ...

. It was constructed from 1968 to 1971 and inaugurated on 1 August 1972. A major technical difficulty in building a radio telescope of 100 m diameter was how to deal with the deformation of the mirror due to gravity when it is rotated to point in a different direction. The mirror must have a precise parabolic shape to focus the radio waves, but a conventionally-designed dish of this size would "sag" slightly when rotated so the mirror loses its parabolic shape. The Effelsberg telescope uses a novel computer-designed mirror support structure which deforms in such a way that the deformed mirror will always take a parabolic shape. The focus will move during such deformation, and the feed antenna suspended in front of the mirror is moved slightly by the computer control system as the telescope is rotated to keep it at the focus. Tests after completion of the telescope showed that the intended accuracy of the mirror surface of 1 mm had not only been met, but exceeded significantly. About 45% of the observing time is available to external astronomers. The Effelsberg 100-m telescope was involved in several surveys, including the one at 408 MHz (73 cm) by Haslam et al.

References

External links

Official website of the Max Planck Institute for Radio Astronomy

Dr Norbert Junkes video interview on Astrotalkuk.org

Effelsberg Official Webpage

{{Authority control Radio telescopes Low-Frequency Array 1971 establishments in West Germany Astronomy in Germany Buildings and structures in Euskirchen (district) Eifel Buildings and structures completed in 1971

Geography

Radio telescope

See also

References

External links