title: Encircled energy for systems with centrally obscured circular pupils.
abstract: The encircled energy is computed for large f/No. aberration-free annular aperture systems with linear obscuration ratios between 0.0 and 0.9. The computations are based on an algorithm due to Hopkins. The results are displayed graphically as contour lines showing the fraction of the total energy which falls within small circles centered on the optical axis in selected receiving planes parallel to the geometric focal plane.
authors.affiliation: Central Institute for Industrial Research, Forskningsveien 1, P.O. Box 350, Blindern, Oslo 3, Norway.
authors.forename: J J
authors.initials: JJ
authors.lastname: Stamnes
authors.forename: H
authors.initials: H
authors.lastname: Heier
authors.forename: S
authors.initials: S
authors.lastname: Ljunggren