Dwingeloo Radio Telescope

The Dwingeloo Radio Telescope stands in the heathland of the Dwingelderveld near the village of Dwingeloo in Drenthe, and it is a landmark of scientific history. Built in the mid-1950s and officially opened in 1956, it was a dish 25 metres across that could be rotated and tilted to point at any part of the sky, and at the time it was the largest steerable radio telescope in the world. Its construction was a major achievement for Dutch astronomy in the years after the Second World War.

Radio astronomy studies the universe through the radio waves emitted by objects in space, rather than the visible light that optical telescopes collect. The field developed quickly after the war, and Dutch scientists took a leading part. At Dwingeloo, researchers mapped the structure of our own galaxy, the Milky Way, by tracking the radio emission of hydrogen gas, a method that revealed its spiral arms. These studies were among the first to give a picture of the galaxy as a whole and are considered a landmark of twentieth-century astronomy.

The telescope later served for other research, and in the 1990s it was used to discover two galaxies, named Dwingeloo 1 and Dwingeloo 2, hidden behind the dust and stars of the Milky Way in a region of the sky that is hard to see in visible light. By then it had been superseded by larger instruments, and it was threatened with demolition. A group of enthusiasts and local people fought to save it, and it was declared a national monument, which gave it protection.

Today the telescope is looked after by volunteers who keep it in working order and welcome visitors. Radio amateurs use it for experiments, including bouncing signals off the Moon, and open days and tours allow members of the public to see the huge structure up close and learn how it works. A visitor centre explains the science and history. The dish is impressive against the open heath, particularly on a clear day.

The telescope lies within the Dwingelderveld National Park, a landscape of heath, woodland and pools that is ideal for walking and cycling. It suits science enthusiasts, families and photographers. Check opening dates, since access is usually limited to certain days or events.