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Optical flat


Accuracy defined by lightband 

1/2 lightband ~ eqv to 1/4 lambda for green monochrome light

How to measure seal face flatness. 

Shanghai trisun

telescope optics



 


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劣質洗衣機入水喉

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ES8311 and ES8388 codec IC

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sharpstar 150mm f/2.8 hyperbolic astrograph

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