In article ,
Jan Panteltje writes:
China develops large aperture optical mirror with high accuracy
http://chinaplus.cri.cn/photo/china/...22/173571.html

Four-meter-diameter aspheric silicon carbide mirror is very
impressive, though the story doesn't quantify the focal ratio, amount
of asphere, or surface accuracy. Does anyone know these numbers or
what the Chinese Academy of Science plans to use the mirror for?

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