Eric Mendelson’s Einsteinturm
Went for an excursion with Sven Eggers of Büro Schwimmer
to visit Mendelson’s Einstein tower before it closed to the public until next October for its summer experiments.
The building, which is about 20 min walk south of Potsdam’s train station, is set in the top of a hill “Telegraphenberg”, at the end of a small garden carved out of the forest. The site is a large compound of buildings used for scientific purposes belonging to the Leibniz-Institut für Astrophysik Potsdam
, it is accesible to the public although you might have to register at the entrance. The inside of the Einsteintower is only accesible via organised tours though.
I was surprised about the size of the building. It is very small, it feels more like vertical house. In fact the only habitable space of the building is the office at the back of the ground floor and a larger basement space. The tower is a hollow shaft with a winding staircase. The shaft contains a wooden structure which itself holds the solar telescope. At the top of the building there is a small dome housing a coelostat. this is a device consisting of two mirrors which are mounted on a rotating structure.
The space around the Coelostat is narrow, It seems to be designed for only one person because there is a single beautiful expressionistic wooden chair and a bench (also designed by Mendelson) holding some electronic equipment. Nevertheless the 15 of us all managed to squeeze in there. The mirrors track the sun and reflect the image into the telescope so that this one does not have to move. At the base of the telescope, on the basement level, we find the spectrograph which guides the light horizontally. The reason for the spectrograph to be placed in the cellar, underground, is that being protected by the earth mound the room keeps a constant temperature which in turn allows to produce a long spectrum to analyse the light.
The sequence of light movements, starting at any position in the sky, being catched at a particular angle through the dome, guided vertically through the telescope and then horizontally by the spectrograph is what gives the building its overall shape which is pretty much like an uppercase L. Although the building is considered a “masterpiece” of expressionistic architecture to my eyes the form is a result of a careful consideration of the technical requirements of the project.
Mendelson planned and built the structure between 19020-1924. It is a Solar Observatory and its original purpose was to help confirm Einstein’s theory of general relativity which states that the lines in the spectrum of the Sun should be shifted due to its large gravitation. Erwin Finlay-Freundlich who was an astronomer and architect, set up the scientific-technical concept about the instrumentation and Mendelson, who was a personal friend of Freundlich’s, followed his guidelines.
Einstein himself never worked in this building although he did visit it. Einstein actually had conservative tastes and after being guided by Mendelson around the building he did not seem to be very excited about, merely saying that it was “organic”.