Mirror system for telescope used for astronomy

摘要

The system includes three mirrors of which two mirrors have a rotationally symmetrical form. A further mirror has either a planar surface or a rotationally symmetrical form. Each of the rotationally symmetrical mirrors can have an aspheric deformation. Four reflections with a folded optical path are achieved by carrying out two reflections either at the first or at the second mirror. All mirrors are rotated against the optical axis about their vertex. All vertexes are provided in a common plane. The optical axis is defined by a main beam (00) of a parallel beam (10) falling onto the first mirror. The inclination of the first mirror can be so adjusted that the second mirror is located outside the incident beam. The second mirror reflects the light to a third mirror surface which is preferably located in the surroundings of the first mirror or is a part of the surface of the first mirror. After the fourth refection at a further mirror surface which can be a part of the second mirror, a real picture is provided. An intermediate picture does not exist. The first mirror has a concave form and either the second or the third mirror has a convex form.