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| Location(s) | Effelsberg,Bad Münstereifel,Euskirchen,Cologne,North Rhine-Westphalia, Germany |
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| Coordinates | 50°31′29″N6°52′58″E / 50.5247°N 6.8828°E /50.5247; 6.8828 |
| Altitude | 319 m (1,047 ft) |
| Wavelength | 408, 86,000 MHz (73.48, 0.35 cm) |
| Diameter | 100 m (328 ft 1 in) |
| Collecting area | 7,850 m2 (84,500 sq ft) |
| Focal length | 30 m (98 ft 5 in) |
| Website | www |
  Location of Effelsberg 100-metre Radio Telescope | |
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TheEffelsberg 100-metre Radio Telescope is aradio telescope in theAhr Hills (part of theEifel) inBad Münstereifel,Germany. Inaugurated in 1972, for 29 years the Effelsberg Radio Telescope was the largest fully steerable radio telescope on Earth, surpassing theLovell Telescope in the UK.[1] In 2000, it was surpassed by theGreen Bank Observatory'sRobert C. Byrd Green Bank Telescope inGreen Bank, US, which has a slightly larger elliptical 100-by-110-metre (330 by 360 ft) aperture.[2]
The telescope is located about 1.3 km northeast of Effelsberg, a southeastern part of the town ofBad Münstereifel inNorth Rhine-Westphalia. It is less than300 m west of the398 m high Hünerberg, which is in neighbouringRhineland-Palatinate. The boundary is a stream, the Effelsberger Bach, which runs only a few metres east of the telescope. The Effelsberger Bach is6.5 km long, flowing from the Effelsberger Wald into the Sahrbach, which in turn flows south and into theAhr river.
A hiking path leads past the telescope; in 2004 part of this was turned into a planet trail with information panels about theSolar System with itsplanets. The trail ends at the39 cm model of theSun next to the visitor centre.
The Effelsberg radio telescope is operated by theMax Planck Institute for Radio Astronomy inBonn, theradio astronomy institute of theMax-Planck-Gesellschaft. It was constructed from 1968 to 1971 and inaugurated on 1 August 1972. A major technical difficulty in building a radio telescope of100 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 preciseparabolic 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 thefeed 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 of1 mm had not only been met, but exceeded significantly.
About 45% of the observing time is available to external astronomers. The Effelsberg 100-metre telescope was involved in several surveys, including the one at408 MHz (73 cm) by Haslam et al.[3][4]
| Parameter | Value |
|---|---|
| Reflector Diameter | 100 m |
| Aperture | 7854 m2 |
| Number of Surface Elements (Panels) | 2,352 |
| Shape Accuracy of Surface | < 0.5mm |
| Focal Length in Prime Focus | 30 m |
| Secondary Mirror Diameter (Gregory-Reflector) | 6.5 m |
| Aperture Stop | N/a |
| • in Prime Focus | f/0.3 |
| • in Secondary Focus | f/3.85 |
| Angular Resolution (Beam Width) | N/a |
| • at21 cm wavelength (1.4 GHz) | 9.4′ |
| • at3 cm wavelength (10 GHz) | 1.15′ |
| • at3.5 mm wavelength (86 GHz) | 10″ |
| Azimuth Track Diameter | 64 m |
| Setting Accuracy of Track | mm |
| Azimuth Range | 480° |
| Maximum Rotation Speed | 30°/min |
| Pointing Accuracy | N/a |
| • Blind Pointing | 10″ |
| • Repeatability | 2″ |
| Power Output of the 16 Azimuth Drives, each | 10.2 kW |
| Radius of Elevation Gear Track | 28 m |
| Elevation Range | 7° to 94° |
| • during observations | 8.1° to 89° |
| Maximum Tilt Speed | 16°/min |
| Power Output of the 4 Elevation Drives, each | 17.5 kW |
| Total Weight | 3200 t |
| Construction Period | 1968–1971 |
| Height of Track above Sea Level | 319 m |
| Commencement of Operation | 1 August 1972 |
| Constructed by | ArbeitsgemeinschaftKrupp/MAN |
Borough ofBad Münstereifel | ||
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| Authority control databases: Geographic |
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