title: Coma compensation in a parabolized Ebert monochromator.
abstract: Coma compensation in a parabolized Ebert monochromator is studied using the plate diagram. It is shown that two different criteria may be used: narrowest images or symmetrical ones; however, both may not be satisfied simultaneously. Symmetrical or narrowest images may be obtained for an extended range of wavelengths with displacement of at least one of the slits. With fixed slits only incomplete compensation may be obtained.
authors.forename: M A
authors.initials: MA
authors.lastname: Gil
authors.forename: J M
authors.initials: JM
authors.lastname: Simon