Kapteyn's measuring device.
Jacobus Kapteyn started to measure all the photographic plates from the Cape Observatory at the end of the nineteenth century. For this purpose he constructed a device. [more]

The Würzburg Riese radar antenna.
During the Second World War, the German army created the Atlantic Wall along the entire European coast, all the way from Norway, through Denmark, the Netherlands, Belgium and France. Part of this Kammhuberlinie were overlapping radarstations, equipped with the so-called Würzburg Riese radar antennas, 7.5 meter in diameter. [more]

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