Timeline of astronomy Rectification of Planetary Theory", eliminated the need for an equant by introducing an extra epicycle, departing from the Ptolemaic system in a way very similar to what Copernicus later also did. Ibn al-Shatir proposed a system that was only approximately geocentric, rather than exactly so, having demonstrated trigonometrically that the Earth was not the exact center of the universe. His rectification is later used in the Copernican model. Nicolaus Copernicus publishes "De revolutionibus orbium coelestium" containing his theory that Earth travels around the Sun. However, he complicates his theory by retaining Plato's perfect circular orbits of the planets. A brilliant
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