Assertion: telescope's element | /r/ObjectUse | used for wide-field imaging
Facets:
value: without spherical aberration
type: OTHER
value: mainly
type: DEGREE
Source sentences:
text: A mid-20th century innovation was catadioptric telescopes such as the Schmidt camera, which use both a spherical mirror and a lens (called a corrector plate) as primary optical elements, mainly used for wide-field imaging without spherical aberration.