title: Testing of flat optical surfaces by the quantitative Foucault method.
abstract: The complete theory of measurement of optical flat mirrors of circular or elliptical shape using the quantitative Foucault method is described here. It has been used in Córdoba since 1939 in a partially intuitive but correct form. The surface, not yet flat and, at times, astigmatic, is assimilated to the sum of a spherical plus a cylindrical dome. The errors of the three possible ways of reckoning are calculated.
authors.forename: M C
authors.initials: MC
authors.lastname: Simon
authors.forename: J M
authors.initials: JM
authors.lastname: Simon