Assertion: telescope's element | /r/HasProperty | the objective
Facets:
Source sentences:
text: The basic scheme is that the primary light-gathering element, the objective (1) (the convex lens or concave mirror used to gather the incoming light), focuses that light from the distant object (4) to a focal plane where it forms a real image (5).
text: The light gathering power depends on the area of the main element (the objective), while the resolving power depends on the diameter.