Assertion: eyepiece's length | /r/HasProperty | dashed green line
Facets:
value: in diagram
type: LOCATION
Source sentences:
text: Equivalently, the effective focal length is the distance from the eye point backward to the location of a plane perpendicular to the optical axis at which the projection angle (β) of the image radius intersects the physical height of the field stop (dashed green line in diagram, above).