Notes

1 Tycho Brahe's name (Tyge Brahe in the original Danish) is pronounced Tee'-ko Braw'-hay. The more common pronunciation of Tye'-ko is not correct (it would be correct if his name were spelled Tæcho). He is commonly referred to by his first name, and so will be called Tycho in the introduction.

2 Pronounced as "vane."

3 In Tycho's time, the biggest controversy was whether or not the universe was heliocentric (or centered on the Sun, as proposed by Copernicus in 1543) or geocentric (or Earth-centered, as was the belief espoused by the ancients and propagated by leading intellectuals of the day). Tycho was in the geocentric camp, but felt that Copernicus's ideas merited attention. As a result, Tycho developed a new system, where the planets (excepting the Earth) orbited the Sun which in turn orbited the central Earth.