Assertion: telescope's lens | /r/CapableOf | collect little light
Facets:
Source sentences:
text: 2) a lens can only be manufactured with limited radius due to the difficulty in making it and defornations that a big lens would have (bending under its own weight); so the lens is bound to have a relatively small diameter and, as a consequence, to collect little light (light for a telescope means infornation about the object; the more light the better!).