From Pendulum Measurements to the GRACE-Mission : on the history of geodesy on Telegrafenberg Hill in Potsdam ; booklet for the Exhibition on the occasion of the 150th anniversery of the foundation of the "Central European Arc Measurement", forerunner of tody's International Association of Geodesy (IAG) [30. August - 27. September 2013 Library Wissenschaftspark Albert Einstein] ; retrospection on perfomed works and scientific results of the Geodetic Institute of Potsdam Höpfner, Joachim