Assertion: telescope's lens | /r/HasProperty | supported around edge
Facets:
Source sentences:
text: the lens is supported only around the edges; as a result, the glass can sag under the force of gravity, distorting the precise curve of the surfaces and blurring the image.
text: A large lens can be quite heavy, supported only around its edge, the lens tends to deform under its weight; mirrors do not have this drawback because it can be supported over its entire back surface