Exhibition 2017 (selection) Surveyor's wheel, London (around 1760) Historical universal theodolite, Pistor & Martins, Berlin (1851) Basis apparatus for surveying geodetic base lines, Gebrüder Brunner, Paris (1876 to 1878) Electromagnetic dip number 1, G. Schulze, Potsdam (around 1900) Marine chronometer, A. Lange & Söhne, Glashütte (1948) Square academic caps made with helmets of the Nationale Volksarmee of Sigmund Jähn and Karl-Heinz Marek (1983) Three-dimensionales model of the so-called "Potsdamer Kartoffel" (Potato of Potsdam) with a 15000 times magnification of the surface's level of the earth, Potsdam (2017)