Assertion: reflecting telescope's mirror | /r/HasProperty | polished
Facets:
value: in 1797
type: TEMPORAL
value: to the wrong shape
type: OTHER
value: on their curved side
type: LOCATION
Source sentences:
text: Therefore, its mirror needed to be polished to an accuracy of 10 nanometers, or about 1/65 of the wavelength of red light.
text: Another advantage is that curved mirrors are polished on their curved side, which prevents light from entering the glass.
text: Analysis of the flawed images revealed that the primary mirror had been polished to the wrong shape.
text: A special 240 in (6.1 m) 25,000 lb (11 t) mirror cell jig was constructed which could employ five different motions when the mirror was ground and polished.
text: The first mirror was last polished in 1797, and was subsequently stored away and lost.