Uranienborg (Swedish: Uraniborg) was an astronomical observatory operated by Tycho Brahe; built circa 1576-1580 on Hven (also spelled Ven or Hveen), an island in the Oresund between Zealand and Scania, at that time belonging to Denmark. It was the first custom-built observatory, and the last to be built without a telescope as its primary instrument. The cornerstone was laid on August 8, 1576. Read more