worldhistoryfacts: The Gaocheng Observatory, the oldest observatory in China. After its establishment in 1279, astronomers there calculated the length of the year to 365.2425 days 300 years before the Europeans. 

worldhistoryfacts: The Gaocheng Observatory, the oldest observatory in China. After its establishment in 1279, astronomers there calculated the length of the year to 365.2425 days 300 years before the Europeans. 

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from: https://ciel62.tumblr.com/post/143922189961