Lobster-eye type X-ray telescopes use reflecting plano mirrors under grazing incidence and can observe a large field of view. As part of a Bavarian-Czech cooperation, two telescopes were build, equipped with mirrors coated with gold and iridium. Their X-ray characterization was carried out at the PANTER test facility, which simulates parallel starlight incident on the telescopes. The telescopes have an angular resolution of about 4 arc minutes in X-rays and a focal length of about 2 meters. The used X-ray mirrors reflect and focus visible light as well; their functionality in the optical regime was checked in laboratory tests. Now another test campaign will be carried out to examine the telescope resolution for real objects of the visible night sky and the imaging properties for star constellations.

Reflective coatings for astronomical X-ray optics were developed at the “Aschaffenburg Competence Center for Astronomical and Space Instrumentation” (ACCASI) since several years. As part of a Bavarian-Czech cooperation between the Technical University of Aschaffenburg and the Czech Technical University of Prague, now two mechanically identical telescopes were built. One telescope optic was equipped with conventional gold-coated mirrors, manufactured by the Czech project partners. The 34 X-ray mirrors of the second telescope use an innovative coating system made of chromium and iridium, which was applied at the Aschaffenburg coating laboratory. Both telescopes are designed according to the bionic principle of a reflecting lobster eye. The optics works with two consecutive reflections on mutually perpendicular mirror surfaces. This enables a large field of view with many square degrees in diameter, which, however, comes at the price of a reduced angular resolution. An extensive X-ray characterization of these telescopes was carried out at the PANTER test facility of MPE, which simulates parallel starlight incident on the telescopes. The telescopes have an angular resolution of about 4 arc minutes in X-rays and a focal length of about 2 meters. Furthermore, the used X-ray mirrors reflect and focus visible light as well and this functionality in the optical regime was checked in laboratory tests. Now another test campaign was done to examine the telescope resolution for real objects of the visible sky and the imaging properties for star constellations. Such functional tests by observing astronomical objects of the visible sky may simplify and accelerate the development of X-ray telescopes for satellite applications.

Beside Wolter I X-ray optics, which are used at most in currently operating X-ray space telescopes, there exist also other optical designs and their usability for space observations is still the matter of studies. This article covers preliminary testing results of an optical module which is based on a modified Kirkpatrick-Baez optics. This X-ray optics, consisting of four sub-modules, was assembled in Prague and tested at the PANTER test facility of MPE afterward. The sub-modules use different reflective coatings, in part developed by our research group, on complementary flat mirrors, which approximate the shape of a Kirkpatrick-Baez optical design. In this contribution we summarise the design of the optical modules, the details of applied coating layers, and the X-ray characterisation results at the PANTER test facility