Stars to navigate by

Quadrant to measure the altitude of the sun. The Round Tower Astronomy Collection

When Christian IV built the Round Tower more than 350 years ago, Denmark was already well known in astronomical circles thanks to Tycho Brahe. When Brahe died in 1601, Christian IV wanted to build a university observatory to continue his work.The Round Tower Observatory was tasked with measuring the position of the stars and planets and hunting for new comets so that astronomers would be able to draw up better charts. However, it was also their duty to learn enough about the stars to help Danish sailors navigate the oceans to places like the East Indies, where the Danes established trading stations.