radiotelescoop

English translation

The text above is the record as published by the Rijksdienst voor het Cultureel Erfgoed, in Dutch. The English below is a machine translation made by TreeAlive, not by the Rijksdienst voor het Cultureel Erfgoed; it has not been checked by a person. Where the two differ, the original is the record. Report a translation error: privacy@treealive.com

Description

Introduction

RADIO TELESCOPE WITH CONTROL BUILDING, situated to the southeast of Dwingeloo, on the border of woodland and heathland, at the edge of the Nationaal Park Dwingelerveld. Due to the sensitivity of the equipment to disturbances, the object, which reaches a maximum height of 30 metres, was built at a peripheral location to minimize the risk of external (electromagnetic) vibrations. Construction began in 1954 (autumn); by mid-1955 the structural work was complete, as was the phase in which the reflector or mirror was placed on the tower. Installation of the machinery and electrical equipment was completed in April 1956. On 17 April 1956 the radio telescope with control building (at that time the largest radio telescope in the world) was officially put into operation by H.R.H. Queen Juliana. The object contains, among other things, a large parabolic reflector (often called a "mirror") and a sensitive, low-noise radio receiver, with which radio waves from the universe could be picked up and the sun and galaxy could be continuously and systematically observed. Leiden professor Jan Hendrik Oort laid the foundation for research into the structure of the galaxy and developed plans for measuring the radio radiation of the Milky Way. Oort's discoveries led to the development of a high-quality technical and scientific apparatus for astronomical observations and related radio-astronomical research. Engineer C.A. (Lex) Muller, collaborator of professor Oort, provided the design of the radio telescope and, together with B.G. (Ben) Hooghoudt, supervised the construction work. Since 1954 the execution has been in the hands of Werkspoor. Other Dutch companies and institutions involved in the construction were Heemaf N.V. in Hengelo (design and execution of the electrical installation), Engineers' and Architects' Office Langhout in Amsterdam (design of concrete foundation), Amsterdamse Ballast Mij N.V. in Amsterdam (execution of concrete foundation work), Metal company Rademakers N.V. in Rotterdam (design and execution of coordinate transformer, the "pilot"), client the Stichting Radiostraling van Zon en Melkweg in collaboration with the Laboratory for Electronic Developments of the Royal Netherlands Navy in Oegstgeest, Physics Laboratory of Philips in Eindhoven and the Dr. Neher Laboratory of the PTT in Leidschendam (design and execution of servo steering). The object weighs 120 tonnes and has no longer served its original scientific function since 1988. The tenant of the radio telescope, Stichting CAMRAS, aims at reuse by amateur astronomers and radio amateurs and stimulates the educational function of the object.

Description

The high-mounted, slightly spider-web-like steel construction ("the mirror") has a diameter of 25.00 m, a depth of 3.25 m and is fitted with tinned metal mesh (steel) with a reflective surface. In 1978 stainless steel mesh panels were installed. The construction of this parabolic mirror, thanks to the consistently implemented triangular system, is regarded as hyperstatic and consists of edge and filler bars and various buckling reducers, further of quadrants, counterweights, focus box and a focus box construction. The antenna is movable in all directions and possesses an automatic tracking mechanism. The entire radio telescope is rotatable about a horizontal axis and suspended from a beak-shaped steel skeleton (necessary to bring the mirror into azimuthal position). This is a 15.00 m high robust truss construction built up of tube bars. The base of this steel skeleton is a square steel frame with a side of 11.70 m and contains the control building. The flat-roofed control building is rotatable and is always positioned behind the reflector. It consists of a steel frame with fibre concrete panels for walls and roof covering. Double glazing is installed in the window recesses; roof light. Internally, among other things, a receiver room, machine room and observation room. Drive by means of servo motors and electric motors. The electrical equipment in the control building consists, among other things, of panels with push-buttons and signalling for manual operation, adjustment knobs and indicator dials of the coordinate transformer as well as the time clocks for solar and sidereal time and a panel with the recorder on which measurements from the 21 cm receiver could be recorded (the recorder has not been used as such since the 1980s, but has since provided the monitoring function of external interference signals). In 1993 the pilot control was removed and replaced by direct control from a control computer. The object has three steel stairs: between the ground level and the control building, while between the control building and the mirror a two-part staircase with a landing leads to and from the tower top, providing access to the elevation movement mechanisms and the equipment at the top of the parabola. The object possesses two drive systems: one for azimuthal movement and one for elevation movement (elevation control completely renewed in 1987). The drive system for elevation movement consists of two separate systems. The whole is mounted rotatably on a spindle, is supported by the spindle and the four wheels on a circular rail and rests below ground level on a rigid foundation, a ring of reinforced concrete with a diameter of approximately 17.00 m, provided with a reinforced base.

Valuation

The movable RADIO TELESCOPE WITH CONTROL BUILDING represents historical and scientific significance on the basis of the international and innovative role the object played in mapping the galaxy, the universe and the discovery of nearby large galaxies. The construction of the radio telescope with machine room is in virtually its original state, hence there is authenticity value and architectural historical significance. The radio telescope with control building at Dwingeloo is the last of three telescopes of this type and represents high rarity value. The leading position of the Netherlands in the internationally oriented astronomical world can be largely traced back to the object. In the control building belonging to the radio telescope, the technical inventory and layout have been largely preserved; in addition to its significance for the history of technology and science, the machine room offers the complementary half of the two-part unit which it forms together with the radio telescope. The object is a guarantee of a remarkable historical sensation due to its dimensions, construction, age, striking appearance and solitary position, particularly as it forms a contrast with the natural surroundings in which the radio telescope with control building is situated, at the edge of the Nationaal Park Dwingelerveld, in an undeveloped area with extensive vistas. The (interference-free) location has remained unchanged since construction and contributes greatly to the historical significance, experiential value and significance of the radio telescope with control building, to be qualified as a landmark.