title: Design of null lenses for testing of elliptical surfaces.
abstract: Null lenses are designed for testing the oblate elliptical surface that is the third mirror of the off-axis three-mirror anastigmatic camera used for remote sensing. Modifying the conventional autostigmatic and autocollimation types of null lenses yields a mixed-type design that has a small annular flat mirror and high sensitivity. Detailed analyses of the sensitivity of the mixed-type null lens system with changes in each surface parameter are described.
authors.affiliation: Agency for Defence Development, Taejon, South Korea. ykim@sunam.kreonet.re.kr
authors.forename: Y S
authors.initials: YS
authors.lastname: Kim
authors.forename: B Y
authors.initials: BY
authors.lastname: Kim
authors.forename: Y W
authors.initials: YW
authors.lastname: Lee