Researchers check the surface of a high accuracy four-meter-aperture optical mirror at Changchun Institute of Optics, Fine Mechanics and Physics, of the Chinese Academy of Sciences, in Changchun, Jilin Province, on Tuesday, August 21, 2018. (Photos: Xinhua)

The 1.6 ton silicon carbide aspheric optical mirror, an important tool for deep space and astronomical observation, passed acceptance tests on Tuesday after nine years of research and development and 18 months manufacturing.

It means China is among the most advanced countries in the world when it comes to making large silicon carbide aspheric optical mirrors.

The high-temperature furnace used to manufacture the high accuracy silicon carbide aspheric optical mirror at Changchun Institute of Optics, Fine Mechanics and Physics, of the Chinese Academy of Sciences, in Changchun, Jilin Province, on Tuesday, August 21, 2018.

Researchers check the surface of a high accuracy four-meter-aperture optical mirror at Changchun Institute of Optics, Fine Mechanics and Physics, of the Chinese Academy of Sciences, in Changchun, Jilin Province, on Tuesday, August 21, 2018.