Assertion: telescope's optic | /r/HasProperty | coated with magnesium fluoride
Facets:
value: fully
type: DEGREE
Source sentences:
text: These eyepieces have all of the features discussed earlier: a wide 50-deg apparent field of view, and the optics are fully coated with magnesium fluoride on every air-to-glass surface (improves contrast and reduces scattering).