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
Battle of the Planets Planets" is the title of American adaptation of this series created by Frank. Frank authorized new footage and hired writers to add dialogue to fit the look of the animation, without reference to original scripts. Of the 105 original "Gatchaman" episodes, 85 were used in the "Battle of the Planets" adaptation produced by Sandy Frank Entertainment in 1978. "Battle of the Planets" cast five young people as G-Force, consisting of Mark, Jason, Princess, Keyop, and Tiny. G-Force protects Earth from the planet Spectra and other attacks from beyond space. The most prominent field commander of the Spectra forces was a