Global Positioning System

Astrolabes are small measuring instruments with a range of uses. They depict the starry sky on a disc, whereby any view of the sky can be simulated at any time. In addition, the height of a star can be measured with the ruler on the back, and so the time, too. Whether for the alignment towards Mecca, the calculation of prayer times, or navigation on the high seas, astrolabes enable global orientation. At the same time, the instrument is symbolic as an early example of #OpenScience. The knowledge for this came from Greek Antiquity, was developed further by Muslim Arabs, and subsequently reached Christian Europe.