Assertion: eyepiece's field | /r/HasProperty | 40 to 50 degrees
Facets:
Source sentences:
text: Orthos are close to perfect eyepieces that have excellent eye relief, nearly non-existent chromatic or spherical aberration, have a fairly flat, wide field of view (40 to 50 degrees), and have little internal reflection.
text: They also had good field of views (about 40 to 50 degrees).