The Paranal Observatory in Chile, 30 kilometers from the site where China plans to build its second overseas observatory. [Photo: baidu.com]

China has signed an agreement to build an observatory in northern Chile, the best place in the world to observe the sky.

The agreement was signed by China's National Astronomical Observatories and the Catholic University of Chile in November, witnessed by Chinese President Xi Jinping and his Chilean counterpart Michelle Bachelet during Xi's week-long Latin America tour.

Thanks to the high altitude, sunny nights and dry air, Chile is believed to be the best observatory site on earth and has attracted many developed countries to build observatory bases there.

As early as 2013, China established an astronomical research center at the Catholic University of Chile. Under its framework experts and scholars of the two countries can share research and observatory results.

Observatories built by other countries in Chile provide 10 percent of its observation time to Chilean experts. As Chile's cooperation partner, Chinese astronomers can also share the 10 percent time in observatories built by other countries.

As the 10 percent time has become insufficient since astronomy is fast developing, China decided to build its own observatory at the site.

It is China's second overseas observatory following the one in Antarctic, and 30 kilometers from Chile's famous Paranal Observatory.