Assertion: newtonian telescope's mirror | /r/CapableOf | focus ray
Facets:
value: on its focal plane
type: LOCATION
Source sentences:
text: The concave mirror focuses the rays on its focal plane.
text: As indicated by the yellow rays in the figure: (1) light enters the open end of the telescope; (2) light rays travel to the primary mirror, where they are reflected and concentrated at the prime focus; (3) a secondary mirror slightly beyond the prime focus reflects and concentrates the rays near a small aperture in the primary mirror; and (4) the image is viewed through an eyepiece.