Assertion: eyepiece | /r/HasProperty | positive
Facets:
value: usually
type: DEGREE
Source sentences:
text: Most eyepieces are positive—that is, they collect (focus) the beams of light rays that pass through them.
text: These eyepieces are usually negative (Huygenian type) and are not capable of being used visually.
text: Most eyepieces are positive—that is, they collect (focus) the beams of light rays that pass through them.