The government of Henan Province in Central China has begun renovating an observatory believed to be the oldest in the world. With a history of 730 years, the observatory was built by Guo Shoujing, a prestigious ancient Chinese astronomer who observed the revolving regularity of the sun, the moon and the stars. On this basis, he calculated correctly that there are 365.24 days in a year. The 20-meter-tall observatory, in a temple southeast of Dengfeng County, is dilapidated. The provincial development and reform commission has allocated 1 million yuan (US$120,480) for repair work.