Orrery on display in Kassel at the Astronomisch-Physikalisches Kabinett and in Dresden at the Mathematisch-Physikalischer Salon. In "De revolutionibus orbium coelestium", published in Nuremberg in 1543, Nicolaus Copernicus challenged the Western teaching of a geocentric universe in which the Sun revolved daily around the Earth. He observed that some Greek philosophers had proposed a heliocentric universe. This simplified the apparent epicyclic motions of the planets, making it feasible to represent the planets' paths as simple circles. This could be modelled by the use of gears. Tycho Brahe's improved instruments made precise observations of the skies (1576–1601), and from these Johannes Kepler
The Mask of the Sun The Mask of the Sun The Mask of the Sun is an graphical interactive fiction game developed by Ultrasoft and published in North America by Brøderbund and in Europe by Ariolasoft. It was released in 1982 for the Apple II, Atari 8-bit family, and Commodore 64. The hero is Mac Steele, an archaeologist who needs to find the Mask of the Sun in order to obtain an antidote to a poison that afflicts him from an artifact that he found. The game mostly takes place in Mexico in the Aztec ruins. Gameplay is text-based; however there are some graphics, including