 He was the first to show clearly that the motion of the solar apogee - when the sun is furthest from earth - is 12.0 seconds per year (the actual value is 11.8 seconds per year).Al-Zarqali also corrected Ptolemy's work, calculating the length of the Mediterranean Sea as 42°, while Ptolemy said it was 62°.His work was quoted multiple times in Nicolaus Copernicus's “De Revolutionibus Orbium Celestium” where he discussed the revolution of the celestial orbs.