Tycho Brahe, born Tyge Ottesen Brahe , was a Danish nobleman famed for his accurate and comprehensive astronomical and planetary observations. Hailing from Scania, now part of modern-day Sweden, Brahe was well known in his lifetime as an astrologer and alchemist.

The Latinized name Tycho Brahe is usually pronounced /ˈtaɪkoʊ ˈbrɑː/ or English. The original Danish name Tyge Ottesen Brahe is pronounced in Modern Standard Danish as Hven and the funding to build the Uraniborg, an early research institute, where he built large astronomical instruments and took many careful measurements. As an astronomer, Tycho worked to combine what he saw as the geometrical benefits of the Copernican system with the philosophical benefits of the Ptolemaic system into his own model of the universe, the Tychonic system. From 1600 until his death in 1601, he was assisted by Johannes Kepler, who would later use Tycho's astronomical information to develop his own theories of astronomy. He is universally referred to as "Tycho" rather than by his surname "Brahe", as was common in Scandinavia.