In the Song (960-1279) and Yuan (1206-1368) dynasties, astronomical instruments reached the limits of what could be achieved with naked-eye observation. Their accuracy could not be increased without the use of optical lenses, but the art of making telescopes was born in Europe.
因為宋元兩代，天文儀器已經達到肉眼測量的極限，除非增加凹凸鏡片，否則精確度不會增加；而望遠鏡技術是在歐洲誕生的。