To keep the Dwingeloo Radio Telescope up to date, changes and improvements have been made continuously. However, for new questions about the structure of the universe larger telescopes are needed that can see more details, such as the WSRT (Westerbork Synthesis Radio Telescope), LOFAR (Low-Frequency Array) and SKA (Square Kilometer Array). For some long-term observation programs, the Dwingeloo Telescope would be very useful, yet there also was the millennium problem for which all sorts of software in the telescope had to be changed. Rewriting the software has not been finished because the WSRT can observe more than ten times as fast. Therefore, ASTRON decided to complete the last long-term observation program in Dwingeloo within a month in Westerbork. Moreover, in 1998 the radio telescope was shut down permanently. Demolition was considered but this would cost more than the scrap-metal would yield. After the telescope was pointed to the zenith the historic instrument was put to rest and handed over to the elements: resulting in algae growth on the mirror and rust in the construction.
To find a better purpose for the telescope, Mark Bentum from ASTRON started searching for people to use the telescope for educational and amateur purposes. This led to a discussion during a KNVWS lecture (Royal Netherlands Association for Meteorology and Astronomy) in Groningen. Next day the newspaper headlined: ‘ASTRON searches new purpose for radio telescope in Dwingeloo’. A few days later, during a special radio broadcast from the Dwingeloo Telescope, astronomer Hugo van Woerden of the Kapteyn Institute in Groningen and Mark Bentum discussed the possibilities and wishes of using the Dwingeloo Radio Telescope by amateurs and for education.
Establishment of the CAMRAS Foundation
Radio amateur Robert Langenhuysen heard this radio interview. Together with Dick Harms, then chairman of VERON (Dutch association for experimental radio research), he approached ASTRON with the request to take over the telescope in order to renovate it, to use it and to open it for visitors, youth, education, amateur astronomers, radio amateurs and for other interested parties. With the ASTRON management they agreed to establish a foundation that would rent the telescope from ASTRON. ASTRON and VERON would each appoint a member to the foundation’s board. After almost a decade of standstill of the telescope, the CAMRAS Foundation was established on January 29, 2007. Maria van der Hoeven, at that time minister of Education, Culture and Science, handed the key of the telescope to Remco den Besten, chairman of the new foundation.
The acronym CAMRAS is derived from C.A. Muller Radio Astronomy Station and refers to Prof. C.A. Muller, electrical engineer, radio amateur and first director of the Radio Observatory in Dwingeloo. A name that connects the worlds of radio amateurs and amateur astronomers, the future users of the telescope.
A first investigation revealed that the construction was severely rusted in many places. The danger that a supporting beam would break was not inconceivable. A lot of distorted steel would be the result and the telescope would then be lost. However, the solid design and the way the construction was realized by Werkspoor in the 1950s did make renovation possible.
Lots of enthusiastic help
With the help of many enthusiastic donators, sponsors and other interested parties, the CAMRAS volunteers have committed themselves to renovate the radio telescope. They tackled all parts of the telescope. And their most important task was to get the 130 tons of steel safely moving again.
The four large running wheels were thoroughly inspected. After ten years of standstill, they were still in an excellent condition. The engines however were in very poor shape. Thanks to a generous donation, CAMRAS was able to replace the motors for the azimuth (horizontal) and elevation (vertical) movement. The motors are equipped with new controllers with speed control and safety guard. The elevation gearboxes and axes were cleaned and re-lubricated. It was quite an achievement and half a year after the establishment of CAMRAS, the telescope was moving again, although initially manually.
The rooms in the control house were thoroughly cleaned, refurbished and painted, but the historical equipment was retained as part of the past. A suspended ceiling in the observation room was donated, the insulation was improved and double glazing was installed. The electrical installation was completely renewed. All wiring was replaced, such as coax cables and cables for electricity and data, through the entire telescope up to the focus box. Although the radio telescope is a historical instrument, without a fiberglass connection it could no longer function properly and CAMRAS was sponsored for this too.
ICT infrastructure and software
On donated computers software was developed for controlling the new motors. In the course of 2008 the control software was sufficiently developed to make the first EME connections. The software developers also ensured that signals from the radio telescope could be streamed via the internet with WebSDR, and that a pulsar and the hydrogen in the Milky Way could be observed.
Antennas and receivers
Of course, the above experiments would not have been possible without suitable antennas and receivers. Volunteers with a lot of knowledge in the field of (microwave) electronics have worked with great dedication to develop that part of the instrumentation of the radio telescope. Some parts they made themselves, other parts were donated or sometimes borrowed from friendly radio amateurs.
Next to the telescope there is a lifting platform that, like the telescope, was not usded for ten years. The lifting platform is needed to place the frontend receivers in the focus box and to connect them. The lifting platform was also overhauled and passed the necessary safety inspection.
Despite the renovation work, the condition of the mirror and construction remained a cause for concern. Corrosion was a big threat. In 2007, the telescope was awarded the status of monument from the post-war reconstruction period (in Dutch) (theme Technique: the recovery and growth of technical and scientific facilities). For the CAMRAS volunteers, this was the opportunity to take part in a TV lottery program about renovation of monuments, with a first prize of € 1 million. The Dwingeloo Radio Telescope ended in an honorable third place, but this did not yield any prize for the necessary renovation.