No abstract

Abstract. In layer-oriented adaptive optics, multiconjugation is performed in a much more efficient way than conventional wavefront sensing. This improved efficiency is impressive for high altitude layers and moderate for ground ones. On the other hand, high altitude layers can be covered with only a limited field of view (where one can search for natural guide stars) while for ground layers the usable field of view is limited essentially by practical reasons. We introduce the further concept of multiple field of view layer-oriented adaptive optics where a combination of sampling and covered field leads easily to sky coverages for 8 m class telescopes that nearly approach the whole sky with the usage solely of natural guide stars. The extension of the concept to much larger apertures is also discussed.

Abstract. The dynamic properties of a layer-oriented multi-conjugate adaptive optics system are examined. It is shown that such a system is stable and closes the loop. A simplified analysis of the achievable correction is presented, in order to define the conditions in which the layer-oriented approach is equivalent to other linear reconstruction schemes. It is found that this approach is equivalent to an optimum one, under certain assumptions, but still retaining the potential advantages of such a novel scheme.

The Layer-Oriented Simulation Tool (LOST) is a numerical simulation code developed for analysis of the performance of multiconjugate adaptive optics modules following a layer-oriented approach. The LOST code computes the atmospheric layers in terms of phase screens and then propagates the phase delays introduced in the natural guide stars' wave fronts by using geometrical optics approximations. These wave fronts are combined in an optical or numerical way, including the effects of wave-front sensors on measurements in terms of phase noise. The LOST code is described, and two applications to layer-oriented modules are briefly presented. We have focus on the Multiconjugate adaptive optics demonstrator to be mounted upon the Very Large Telescope and on the Near-IR-Visible Adaptive Interferometer for Astronomy (NIRVANA) interferometric system to be installed on the combined focus of the Large Binocular Telescope.

The mirror assembly of the ESA New -Advanced Telescope for High-ENergy Astrophysics (New-ATHENA) will be the largest X-ray optics ever built. Indeed, its unprecedented size, mass and focal length create great difficulties for the ground calibration. The VERT-X project aims at developing an innovative calibration facility which will be able to accomplish to this extremely challenging task. The design is based on a 2.5 cm 2 parallel beam produced by an X-ray source positioned in the focus of a highly performing collimator. In order to cover the whole mirror, the beam will be accurately moved by a raster-scan with the capability to tilt up to 3 degrees in order to test the off-axis performance and the out of field stray-light. The whole system is enclosed in a cylindrical vacuum chamber about 20m high and with a diameter ranging from 7 to 4m. By design, VERT-X will be able to measure the New-ATHENA mirror half energy width (HEW) with a precision of 0.1", all over the field of view, with the source size, the collimator error and the raster scan tracking accuracy being the most important terms of the error budget. The VERT-X project, started in 2018, is financed by ESA and conducted by a consortium that includes INAF together with EIE, Media Lario, BCV Progetti and Apogeo Space. This paper presents the current state of the development and manufacturing of the most critical systems of the facility, namely the raster-scan mechanism and the source-collimator vertical assembly.