title: The optical system for the 3.5-m ESO telescope.
abstract: The optical design of a mirror telescope with a free aperture of 3.5 m is described. Observations can be made in the Cassegrain (RC) focus f/8, in the direct focus f/3, and in the coudé focus f/30. The results of ray tracing in the form of spot diagrams are dealt with. Some technological problems are discussed.
authors.forename: H
authors.initials: H
authors.lastname: Köhler