Assertion: microscope's lens | /r/HasProperty | advanced design
Facets:
value: during the late 16th century
type: TEMPORAL
value: very
type: DEGREE
Source sentences:
text: Zacharias Jansen and his father's design used a bi-convex eyepiece lens and a plano-convex objective lens, which was considered to be a very advanced design during the late 16th century.