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The ESO Extremely Large Telescope (ELT) has been in construction since 2014. In parallel with the construction of the telescope, ESO has entered into agreements with consortia in the ESO member states to build the first instruments for that telescope. To meet the telescope science goals, the ambitious instrument plan includes two instruments for first light: an optical to near-infrared integral field spectrograph with a dedicated adaptive optics system (HARMONI) and a near-infrared camera with simple spectrograph (MICADO) behind a multi-conjugate adaptive optics module (MAORY). The next instrument will be a mid-infrared imager and spectrograph (METIS). Plans to follow this first suite of instruments include a high-resolution spectrograph (HIRES) and a multi-object spectrograph (MOSAIC). Technology development is underway to prepare for building the ELT Planetary Camera and Spectrograph. An overview of the telescope and its instruments is given.

In this paper we will report on the status of the instrumentation project for the European Southern Observatory's Extremely Large Telescope (ELT). Three instruments are in the construction phase: HARMONI, MICADO and METIS. The multi-conjugate adaptive optics system for MICADO, MAORY, is also under development. Preliminary Design Reviews of all of these systems are planned to be completed by mid-2019. The construction of a laser tomographic module for HARMONI is part of "Phase 2" of the ELT: the design has been advanced to Preliminary Design level in order to define the interface to the HARMONI spectrograph. Preparations for the next instruments have also been proceeding in parallel with the development of these instruments. Conceptual design studies for the multi-object spectrograph MOSAIC, and for the high resolution spectrograph HIRES have been completed and reviewed. We present the current design of each of these instruments and will summarise the work ongoing at ESO related to their development.

A suite of seven instruments and associated AO systems have been planned as the "E-ELT Instrumentation Roadmap". Following the E-ELT project approval in December 2014, rapid progress has been made in organising and signing the agreements for construction with European universities and institutes. Three instruments (HARMONI, MICADO and METIS) and one MCAO module (MAORY) have now been approved for construction. In addition, Phase-A studies have begun for the next two instruments - a multi-object spectrograph and high-resolution spectrograph. Technology development is also ongoing in preparation for the final instrument in the roadmap, the planetary camera and spectrograph. We present a summary of the status and capabilities of this first set of instruments for the E-ELT.

ESO is undertaking a large upgrade of the infrastructure on Cerro Paranal in order to integrate the 2nd generation of interferometric instruments Gravity and MATISSE, and increase its performance. This upgrade started mid 2014 with the construction of a service station for the Auxiliary Telescopes and will end with the implementation of the adaptive optics system for the Auxiliary telescope (NAOMI) in 2018. This upgrade has an impact on the infrastructure of the VLTI, as well as its sub-systems and scientific instruments.

The New Adaptive Optics Module for Interferometry (NAOMI) will be developed for and installed at the 1.8-metre Auxiliary Telescopes (ATs) at ESO Paranal. The goal of the project is to equip all four ATs with a low-order Shack– Hartmann adaptive optics system operating in the visible. By improving the wavefront quality delivered by the ATs for guide stars brighter than R = 13 mag, NAOMI will make the existing interferometer performance less dependent on the seeing conditions. Fed with higher and more stable Strehl, the fringe tracker(s) will achieve the fringe stability necessary to reach the full performance of the second-generation instruments GRAVITY and MATISSE.

In vitro test systems have to be optimized to reduce preclinical failure rates. Therefore, we have introduced a new innovative system which mimics physiological conditions and enables vascularisation in bioreactors. Thus, we have developed test systems for intestinal uptake studies, for airway infections and for different tumour entities, e. g. lung cancer. A further approach presents the ex vivo cornea test system for irritation studies.

Turbulence in Earth's atmosphere severely limits the achievable image quality of ground-based optical telescopes. With the technique of adaptive optics, the induced distortions of the light can be measured and corrected in real time, regaining nearly diffraction limited performance. Unfortunately, when using a single guide star to measure the distortions, the correction is only useful within a small angular area with a radius of ∼3 centered on the guide star. This paper presents a laboratory setup, using four simulated natural guide stars and one deformable mirror to measure and correct turbulence-induced distortions over ∼ . With such �� �� 35 # 22 a layer-oriented ground-layer adaptive optics (GLAO) system, the area of useful correction is significantly increased. We characterize a test bed for such a system in static and dynamic operation and verify the principles of the layer-oriented technique in closed loop operation. Furthermore, we study the influence of nonconjugated turbulent layers and the effect of brightness variations of the guide stars and derive results very similar to theoretical predictions and numerical simulations.

We present the results of optical turbulence measurements conducted with a Generalized SCIDAR (scintillation detection and ranging) at Mount Graham during 16 nights in 2004 and 2005 at the Vatican Advanced Technology Telescope. The principle of the data reduction process is shown, as is the validation of the obtained results. From the measured and wind speed profiles, the astroclimatic parameters, such as seeing , isoplanatic 2 C e N 0 angle , wave-front coherence time , and isopistonic angle , are calculated, and their seasonal variation is ct c 00 P studied. With subtraction of the dome seeing, we obtained median values for (0.67), (2.7), (3.6 ms), ec t 00 0 and (3.3) that indicate that the astronomical seeing at Mount Graham is comparable to the best sites in the cP world. The seasonal variation of the vertical structure of the profiles is studied, and the contribution by the 2 CN ground-layer turbulence is analyzed. Furthermore, typical discretized profiles that are suitable for numerical 2 CN simulations are determined. Online material: color figures

LINC-NIRVANA is a Fizeau (imaging) interferometer exploiting the full spatial resolution of a 23 m class telescope in the combined beam of the Large Binocular Telescope supported through Multi-Conjugated Adaptive Optics (MCAO). By means of science cases, we show how LINC-NIRVANA takes advantage of the MCAO, increasing the sky coverage of the instrument and the field of view for the Fringe and Flexure tracker. We introduce the MCAO system of LINC-NIRVANA in detail, which in a first step will be installed with two deformable mirrors per arm and has the provision to be upgraded with a third mirror. The MCAO system implements several novel concepts proposed for extremely large telescopes, such as layer oriented MCAO, optical co-adding of guide stars, or Multiple Field of View sensing. LINC-NIRVANA will demonstrate some of the concepts for the first time on sky. To cite this article: W. Gaessler et. al., C. R. Physique 6 (2005).

A puzzle called ’’M_{13} ‘‘ J. H. Conway has described recently is explained. We report an implementation of the puzzle in the programming language Java. The program allows the human user to ’’play M_{13}‘‘ interactively (and to cheat by solving it automatically). The program is an example on how to bring to life a nice piece of discrete mathematics. In this sense it presents not only a didactical way of seeing ’’mathematics at work‘‘, but also displays the stabilizer chain method developed by C. Sims to solve group theoretic puzzles, the most famous of which being Rubik‘s cube.

Due to the exposed location of the Wendelstein observatory on the steep summit of mount Wendelstein no road exists to transport telescope components and heavy equipment to the observatory in order to install the new 2m Fraunhofer Telescope Wendelstein (FTW) in its new dome. A two step installation concept was therefore followed to mitigate any risks that essential hardware would not work once installed on the mountain. This paper reports on the telescope factory assembly and tests, including on-sky tests, which were performed in early summer 2011 at the factory site to make sure, that the telescope and all essential subsystems are working properly before the telescope would be installed on the mountain. The telescope was disassembled again to be transported to the mountain in summer. Lifting of all structural subsystems and the optics up to the mountain observatory with the help of a heavy lift helicopter will be presented in detail, also looking at specific design drivers, logistic aspects and special tools for installation of the telescope and its mirrors in its new dome. Handling and transport concept for the M1 mirror installation, which also will have to be used when the mirror is disassembled for recoating, are presented. Up to end of 2011 the telescope installation and pre-alignment could be completed including first on-sky tests. The system will undergo a detailed performance test campaign in the first halve of 2012. Current performance results of these commissioning activities will be reported.

The Subaru laser guide star adaptive optics system (AO188) was installed at the Nasmyth focus of the Subaru Telescope on October 2006 and it is in operation with the natural guide star (NGS) mode. The operation of the laser guide star (LGS) mode started on January 2010. A visible low-order wavefront sensor (LOWFS) was built to measure tip-tilt and defocus terms of wavefront by using a single NGS within a 2.7 arcmin diameter field when an LGS is used for high-order wavefront sensing with the 188-element curvature based wavefront sensor. This LOWFS is a 2 × 2 sub-aperture Shack-Hartmann sensor with 16 photon-counting avalanche photodiode (APD) modules. A 4×4-element lenslet array is located after the 2 × 2 sub-aperture Shack-Hartmann lenslet array and it is coupled with the APD modules through optical fibers. The field of view of the LOWFS is 4 arcsec in diameter. It has own guide star acquisition unit, acquisition and pupil cameras, and atmospheric dispersion corrector. We describe the design, construction, and integration of this low-order wavefront sensor.

A tip/tilt off-load function from AO188 deformable mirror mount to Subaru telescope infrared secondary mirror has been implemented and tested. The function is effective to reduce the influence of strong background pattern at thermal infrared wavelengths. We describe the function and report the test results in this paper.

In this paper, we present the science path ADC unit (atmospheric dispersion corrector) for the AO188 Adaptive Optics System of the Subaru Telescope. The AO188 instrument is a curvature-based Adaptive Optics system with 188 subapertures and achieves good correction down to shorter wavelengths like J-band. At these wavelengths, the atmospheric dispersion within the band becomes significant and thus a correction of the atmospheric dispersion is essential to reach diffraction-limited image quality. We give an overview of the requirements, the final optical and mechanical design of the ADC unit, as well as the structure of its control software.

The current status of commissioning and recent results in performance of Subaru laser guide star adaptive optics system is presented. After the first light using natural guide stars with limited configuration of the system in October 2006, we concentrated to complete a final configuration for a natural guide star to serve AO188 to an open use observation. On sky test with full configurations using natural guide star started in August 2008, and opened to a public one month later. We continuously achieved around 0.6 to 0.7 of Strehl ratio at K band using a bright guide star around 9th to 10th magnitude in R band. We found an unexpectedly large wavefront error in our laser launching telescope. The modification to fix this large wavefront error was made and we resumed the characterization of a laser guide star in February 2009. Finally we obtained a round-shaped laser guide star, whose image size is about 1.2 to 1.6 arcsec under the typical seeing condition. We are in the final phase of commissioning. A diffraction limited image by our AO system using a laser guide star will be obtained in the end of 2010. An open use observation with laser guide star system will start in the middle of 2011.

We report recent development in real time control system of Subaru adaptive optics system. The main topic is modification of the real time control system for laser guide star operation. The primary change is appending lower order wave-front sensor. And also, an auxiliary tip-tilt and focus control are appended before higher order waver-front sensor to absorb the perturbation of the laser beam and height of sodium layer. Our implementations using the control gain matrix are introduced thoroughly from the basis of the system design and down to the details. Also, other new function and prospects in the near future will be presented for the cascaded average monitor and the time domain over sampling.

We are developing a laser guide star (LGS) system for the 188-elements Adaptive Optics system (AO188) of theSubaru telescope. In this paper we describe the results of the performance tests of the LGS system. The beamthat excites sodium atoms at 90 km altitude of the LGS is generated by the following sequence. The sourceof the beam is a quasi-CW mode locked sum-frequency generating 589 nm laser. This laser beam propagatesthrough a diagnostics system for mea suring the wavelength and the beam q uality. Then it couples into a solid-core photonic crystal “ber cable for transmitting the beam to a telescope for launching the beam (LLT: LaserLaunching Telescope). The output beam from this “ber cable is collimated by the optics mounted on theLLT. This collimated beam is expanded by the LLT and launched into the sky. We executed several engineeringobservations of the LGS system from 2009 for con“rming the performance of all the components in this sequence.We also report the quality of the LGS.Keywords: Adaptive Optics, Laser Guide Star, Sodium Laser

Subaru adaptive optics system (AO188) is an 188-elements curvature sensor adaptive optics system that is operated in both natural and laser guide star modes. AO188 was installed at Nasmyth platform of the Subaru telescope and it has been successfully operating in the natural guide star mode since October 2008. The performance of AO188 in the natural guide star mode has been well verified from on-sky data obtained with the infrared camera and spectrograph (IRCS). Under normal seeing condition, AO188 achieves K-band Strehl ratio between 60% and 70% using R =9 .0 magnitude natural guide stars and it works well with faint guide stars down to R =1 6.5 magnitude. We measured the FWHM and Strehl ratio of stellar images in globular clusters and found that the isoplanatic angle is approximately 30 arcsec. In this paper, we describe an overview of the operation procedure for AO188, as well as its performance such as angular resolution, Strehl ration, and sensitivity gain for detecting faint objects.

Laboratory and on-sky experience suggests that the integration of big astronomical instruments, specially of a complex interferometric system, is a challenging process. LINC-NIRVANA is the Fizeau interferometric imager for the Large Binocular Telescope (LBT). Simulating the final operating environment of every system component has shown how critical is the presence of flexures, vibrations and thermal expansion. Assembling and aligning the opto-mechanical sub-systems will require an absolute reference which is not affected by static displacements or positioning errors. A multi-purpose calibration unit has been designed to ensure the quality of the alignment of optics and detectors and the reliability of the mechanical setup. This new compact and light-weighted unit is characterized by sophisticated kinematics, simple mechanical design and composite materials. In addition, the reduced number of motorized axis improves the stiffness and lowers the angular displacements due to moving parts. The modular concept integrates several light sources to provide the proper calibration reference for the different sub-systems of LINC-NIRVANA. For the standard alignment of the optics an absolute reference fiber will be used. For flatfielding of the detectors the unit provides an integrating sphere, and a special rotating multi-fiber plate (infrared and visible) is used to calibrate the advanced adaptive optics and the fringe-tracking systems. A module to control non-common path aberrations (Flattening of Deformable Mirrors) is also provided.

HiCIAO is a near-infrared, high contrast instrument which is specifically designed for searches and studies for extrasolar planets and proto-planetary/debris disks on the Subaru 8.2 m telescope. A coronagraph technique and three differential observing modes, i.e., a dual-beam simultaneous polarimetric differential imaging mode, quad-beam simultaneous spectral differential imaging mode, and angular differential imaging mode, are used to extract faint objects from the sea of speckle around bright stars. We describe the instrument performances verified in the laboratory and during the commissioning period. Readout noise with a correlated double sampling method is 15 e- using the Sidecar ASIC controller with the HAWAII-2RG detector array, and it is as low as 5 e- with a multiple sampling method. Strehl ratio obtained by HiCIAO on the sky combined with the 188-actuator adaptive optics system (AO188) is 0.4 and 0.7 in the H and K-band, respectively, with natural guide stars that have R ~ 5 and under median seeing conditions. Image distortion is correctable to 7 milli-arcsec level using the ACS data as a reference image. Examples of contrast performances in the observing modes are presented from data obtained during the commissioning period. An observation for HR 8799 in the angular differential imaging mode shows a clear detection of three known planets, demonstrating the high contrast capability of AO188+HiCIAO.

Adaptive optics system with a laser guide star at Subaru Telescope is under commission. Characteristics of laser guide star, which is produced by all-solid state sum frequency laser at 589 nm, are presented.

We are testing a photon‐counting electron multiplying CCD (EMCCD) for use in the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. We intend to use EMCCD technology on the SCExAO system for (1) high performance wavefront sensing for Extreme‐AO and (2) diffraction limited visible light science imaging. For both applications, the ability to operate in photon‐counting mode is highly advantageous, and we are currently conducting laboratory tests to quantify the EMCCD performance for these applications. The EMCCD technology is also attractive as a higher sensitivity alternative to the Avalanche Photodiodes (APDs) currently used by Subaru 188‐actuator adaptive optics system.

The Large Binocular Telescope (LBT) is an international collaboration, with partners from the United States, Italy, and Germany. The telescope uses two 8.4-meter diameter primary mirrors to produce coherent images with the combined light along with adaptive optics. The correct functioning and optimum performance of the LBT is only achieved through a complex interplay of various optical elements. Each of these elements has its individual vibration behaviour, and therefore it is necessary to characterize the LBT as a distributed vibration system. LINC-NIRVANA is a near-infrared image-plane beam combiner with advanced, multi-conjugated adaptive optics, and one of the interferometric instruments for the Large Binocular Telescope (LBT). Its spectral range goes from 1.0 μm to 2.45 μm, therefore the requirements for the maximum optical path difference (OPD) are very tight (λ/10 ~ 100 nm). 1 During two dedicated campaigns, the vibrations introduced by various actuators were measured using different kinds of sensors. The evaluation of the obtained data allows an estimation of the frequency and amplitude contributions of the individual vibration sources. Until the final state of the LBT is reached, further measurements are necessary to optimize and adapt the equipment and also the investigated elements and configurations (measurement points and directions, number of sensors, etc.).

Since November 2004 we measured the optical turbulence ( C 2N pro“les) with a Generalized Scidar (GS) placed atthe focus of the Vatican Advanced Technology Telescope at Mt.Graham, Arizona. The present statistic consistsin measurements related to 43 nights covering dierent p eriods of the solar year. In this paper we calculate thestatistics of the astroclimatic parameters ( C 2N , seeing , isoplanatic angle 0 , wavefront coherence time 0 )andwe compare these values with those measured above othe r top level astronomic sites. All pro“les are reducedinto a form suitable to be used as inputs for adaptive optics point spread function simulations for the conceptualdesign of the Laser Guide Star Facility supported by a GLAO system of the Large Binocular Telescope. WithGS measurements done observing wide binaries (30-35 arcsec), the turbulence in the “rst kilometer above theground is characterized with the vertical resolution (200-250 m) required for the optimization of a 4 arcmin“eld of view AO system. It is the “rst time that are published measurements of the optical turbulence verticaldistribution above a mid-latitude site with such a high vertical resolution and such a high statistical reliability.On 8 of those nights, employing cross-correlation scintillation maps of wide binaries and the method describedin Ref.[1] we characterize the distribution of the optical turbulence in the “rst kilometer at the extremely highvertical resolution of 20-30 meters.Keywords: turbulence, site testing, atmos pheric eects, image processing

LINC-NIRVANA is the near-infrared homothetic imaging camera for the Large Binocular Telescope. Once operational, it will provide an unprecedented combination of angular resolution, sensitivity and field of view. Its Fringe and Flexure Tracking System (FFTS) is mandatory for an efficient interferometric operation of LINC-NIRVANA. It is tailored to compensate low-order phase perturbations in real-time to allow for a time-stable interference pattern in the focal plane of the science camera during the integration. Two independent control loops are realized within FFTS: A cophasing loop continuously monitors and corrects for atmospheric and instrumental differential piston between the two arms of the interferometer. A second loop controls common and differential image motion resulting from changing orientations of the two optical axes of the interferometer. Such changes are caused by flexure but also by atmospheric dispersion. Both loops obtain their input signals from different quadrants of a NIR focal plane array. A piezo-driven piston mirror in front of the beam combining optics serves as actuator in the cophasing loop. Differential piston is determined by fitting a parameterized analytical model to the observed point spread function of a reference target. Tip-tilt corrections in the flexure loop are applied via the secondary mirrors. Image motion is sensed for each optical axis individually in out-of-focus images of the same reference target. In this contribution we present the principles of operation, the latest changes in the opto-mechanical design, the current status of the hardware development.

A Fizeau interferometer combines the light of several telescopes to obtain panoramic images with an angularresolution equivalent to the longest edge-to-edge separation in the system. The overall performance of a Fizeauinterferometer depends critically on the performance of the (MC)AO system and the eciency of atmosphericpiston correction, but also on other eects like alignmen t accuracies, “lter bandwidth s, tracking errors, atmo-spheric dispersion and “eld rotation. Due to the mutual dependence, Strehl ratio or fringe contrast like inconventional Adaptive Optics systems or pupil plane interferometers are not sucient for a consice assessmentof the performance of such an instrument. As a measure for the actual performance, we propose to use the ratioR23, which is the actual high-spatial frequency information in the images, divided by what could be measuredin principal with a 23m telescope (a s the LBT). We present the theoretical concept of this method and showthe results of various simulations of the abovementioned eects as an application to LINC-NIRVANA, a Fizeauinterferometer currently being built for the LBT.Keywords: Interferometry, Fizea u Imaging, wavefront error, Adaptive Optics

LINC-NIRVANA is an infrared camera that will work in Fizeau interferometric way at the Large Binocular Telescope (LBT). It will take advantage of a field corrected from two MCAO systems, one for each arm, based on the Layer Oriented Technique and using solely Natural Guide Stars. For each arm, there will be two wavefront sensors, one conjugated to the Ground and one conjugated to a selectable altitude, ranging from 4 to 15 Km. They will explore different fields of view for the wavefront sensing operations, accordingly to the Multiple Field of View concept, and particularly the inner 2 arcminutes FoV will be used to select the references for the high layer wavefront sensor while the ground one will explore a wider anular field, going from 2 to 6 arcminutes in diameter. The wavefront sensors are under INAF responsibility, and their construction is ongoing in different italian observatories. Here we report on progress, and particularly on the test ongoing in Padova observatory on the Ground Layer Wavefront Sensor.

LINC-NIRVANA is an infrared camera working in Fizeau interferometric mode. The beams coming from the two primary mirrors of the LBT are corrected for the effects of the atmospheric turbulence by two Multi-Conjugate Adaptive Optics (MCAO) systems, working in a scientific field of view of 2 arcminutes. One single arm MCAO system includes two wave-front sensors, driving two deformable mirrors, one for the ground layer correction (LBT secondary mirror) and one for the correction of a mid-high layer (up to a maximum distance of 15 km). The first of the two Mid-High Wavefront Sensors (MHWS) was integrated and tested as a stand-alone unit in the laboratory at INAF-Osservatorio Astronomico di Bologna, where the telescope was simulated by means of a simple afocal system illuminated by a set of optical fibers. Then the module was delivered to the MPIA laboratories in Heidelberg, where is going to be integrated and aligned to the post-focal optical relay of one LINC-NIRVANA arm, including the deformable mirror. A number of tests are in progress at the moment of this writing, in order to characterize and optimize the system functionalities and performance. A report is presented about the status of this work.

LINC-NIRVANA (LN) is a German-Italian Fizeau (imaging) interferometer for the Large Binocular Telescope (LBT). The Instrument Control Software (ICS) of this instrument is a hierarchical, distributed software package, which runs on several computers. In this paper we present the bottom layer of the hierarchy - the Basic Device Application (BASDA) layer. This layer simplifies the development of the ICS through a general driver architecture, which supports different types of hardware. This generic device architecture provides a high level interface to encapsulate the hardware dependent driver. The benefit of such a device architecture is to keep the basic device-driver layer flexible and independent from the hardware, and to keep the hardware transparent to the ICS. Additionally, the basic device-driver layer supports interfaces to IDL based applications for calibration and laboratory testing of astronomical instruments, and interfaces to engineering GUIs that allow to maintain the software components easily.

We built an optical system that emulates the optical characteristics of an 8m-class telescope like the VLT and that contains rotating glass plates phase screens to generate realistic atmosphere-like optical turbulence. Together with an array of single mode fibers fed from white light sources to simulate various stellar configurations, we can investigate the behavior of different single or multi-conjugate adaptive optics setups. In this paper we present the characteristics of phase screens etched on glass plates surfaces obtained from Silios Technologies.

LINC-NIRVANA is an infrared camera that will work in Fizeau interferometric way at the Large Binocular Telescope (LBT). The two beams that will be combined in the camera are corrected by an MCAO system, aiming to cancel the turbulence in a scientific field of view of 2 arcminutes. The MCAO wavefront sensors will be two for each arm, with the task to sense the atmosphere at two different altitudes (the ground one and a second height variable between a few kilometers and a maximum of 15 kilometers). The first wavefront sensor, namely the Ground layer Wavefront sensor (GWS), will drive the secondary adaptive mirror of LBT, while the second wavefront sensor, namely the Mid High layer Wavefront Sensor (MHWS) will drive a commercial deformable mirror which will also have the possibility to be conjugated to the same altitude of the correspondent wavefront sensor. The entire system is of course duplicated for the two telescopes, and is based on the Multiple Field of View (MFoV) Layer Oriented (LO) technique, having thus different FoV to select the suitable references for the two wavefront sensor: the GWS will use the light of an annular field of view from 2 to 6 arcminutes, while the MHWS will use the central 2 arcminutes part of the FoV. After LINC-NIRVANA has accomplished the final design review, we describe the MFoV wavefront sensing system together with its current status.

We present a laboratory setup of a Ground-Layer Adaptive Optics system. This system is a scaled-down version of the MCAO system of MAD (a MCAO system for the VLT) / LINC-NIRVANA (a Fizeau Imager for the LBT) and measures the wavefront aberrations with 4 pyramids in a layer-oriented fashion with optical co-addition. The laboratory setup contains besides the wavefront-sensing unit a telescope-simulator, a dynamic turbulence generator and a Deformable Mirror for the wavefront correction. We describe the overall system and its single components, open- and closed-loop measurements of the characteristics of a system working in GLAO mode and first results when using a Kalman filter for the control of the wavefront reconstruction process.

By using the SCIDAR instrument at the VATT on the top of Mt. Graham and a very wide binary star with a separtion of 35", the vertical structure of the turbulence in the first few hundred meters above the telescope was measured. When using such a binary and analysing the cross-correlation images, a vertical resolution for the turbulence profile of a few tens of meters can be achieved near the ground. This permits to determine the inner structure and the wind sheer of the single turbulent layers inside the ground-layer. We present the principles and the data-reduction process of this method and show first results obtained with this method at Mt. Graham. As an application, we estimate the fraction of the turbulence between the dome of the VATT and the primary mirror of the LBT.

ELTs depend on Adaptive Optics (AO) to reach the diffraction limit. To achieve sufficient sky coverage with AO, several Laser Guide Stars (LGS) will be needed, but the finite distance of the LGSs introduces optical problems which can not be solved easily, especially at telescopes with a diameter larger than 30m. PIGS (Pseudo Infinite Guide Star) is a novel sensing technique proposed to overcome some of these problems by using a slit mask and a reflective rod measuring in radial and azimuthal direction the wavefront abberations. The sensor was already demonstrated with a single LGS in laboratory and on sky. Currently we investigate the PIGS concept in a MCAO (Multi Conjugated Adaptive Optics) fashion by building a test setup in the laboratory. MCAO will solve the cone effect, one of the remaining problems with PIGS. The PIGS MCAO experiment goals on engineering problems and demonstration of the layer orientated concept with the PIGS technique. The PIGS concept and its extension to MCAO will be described and preliminary results presented.

The Mid-High Wavefront Sensors (MHWS) are components of the adaptive optics system of LINC-NIRVANA, the Fizeau interferometer that will be mounted at the LBT. These sensors, one for each telescope arm, will measure the atmospheric turbulence in the high altitude layers, using up to 8 reference stars in a 2 arcmin Field of View, and they will be coupled with two Ground Layer WFSs that will measure the lower part of the atmospheric turbulence using up to 12 stars over an annular Field of View from 2 to 6 arcmin in diameter. We will describe the opto-mechanical layout of the MHWS and the Assembly, Integration and Test (AIT) phase of the first sensor in the laboratory of the Bologna Observatory.

Combining the two 8.4 m telescopes of the Large Binocular Telescope 1 (LBT) offers the unique possibility to achieve diffraction limited images with 23 m spatial resolution. This requires an interferometric superposition of the two telescope beams in a Fizeau-type interferometer. LINC-NIRVANA delivers a 10 arcsec x 10 arcsec panoramic field of view with 5 mas pixel size. In addition to delivering diffraction limited, single-telescope images, the optics have several additional constraints imposed by interferometric operation. In this paper, we describe the evolution of the optical design and how the individual optical subsystems were developed in parallel to provide optimal combined performance. We also present an alignment strategy to setup the optics and to achieve zero optical path difference.

Deformable mirrors with more than 1000 actuators are currently being developed for eXtreme AO applications, either for ELTs, high order Adaptive Optics correction in the visible light, or combination of both. The large number of actuators, the high frequency at which these DMs are to be used and further advancement in schemes for AO control, requiring a growing degree of knowledge of the AO system for efficient correction, sets special requirements on the characterization of the static and dynamic behavior of the DM. In the light of CHEOPS, an extreme-AO Planet Finder project, we have characterized a Xinetics deformable mirrors with 349 actuators. This mirror serves as a proxy for the characterization of a >1200 actuator DM of a similar type, which will be implemented in CHEOPS. In this paper we present the results of this characterization. Special attention was paid to mirror properties like hysteresis, non-linearity, temperature dependence and influence function.

On the way to the Extremely Large Telescopes (ELT) the Large Binocular Telescope (LBT) is an intermediate step. The two 8.4m mirrors create a masked aperture of 23m. LINC-NIRVANA is an instrument taking advantage of this opportunity. It will get, by means of Multi-Conjugated Adaptive Optics (MCAO), a moderate Strehl Ratio over a 2 arcmin field of view, which is used for Fizeau (imaging) interferometry in J,H and K. Several MCAO concepts, which are proposed for ELTs, will be proven with this instrument. Studies of sub-systems are done in the laboratory and the option to test them on sky are kept open. We will show the implementation of the MCAO concepts and control aspects of the instrument and present the road map to the final installation at LBT. Major milestones of LINC-NIRVANA, like preliminary design review or final design review are already done or in preparation. LINC-NIRVANA is one of the few MCAO instruments in the world which will see first light and go into operation within the next years.

Several multi-conjugate adaptive optics (MCAO) systems using the layer-oriented approach are under construction and will soon be tested at different facilities in several instruments. One of these instruments is LINC-NIRVANA, a Fizeau interferometer for the Large Binocular Telescope (LBT). This instrument uses a ground layer wavefront sensor (GWS) and a combined mid-high layer wavefront sensor (MHWS) with different fields of view (concept of multiple field of view), a 2-6 arcmin annular ring for the GWS and a 2 arcmin diameter central field of view for the MHWS. Both sensors are Pyramid wavefront sensors which optically co-add light from multiple natural guide stars. The opto-mechanical problems concerning these sensors are related to the fast focal ratio of the beam on the pyramids coupled with the available pixelscale of detectors. This leads to very tight requirements on the moving systems (linear stages) for the star enlargers (SE) used to pick off the light of individual stars. As there are 40 star enlargers in the overall system, additional efforts were put into the alignment system of the optics of the star enlargers and the reduction in size of the star enlargers to minimize the distance between available guide stars.

LINC-NIRVANA is an imaging interferometer for the Large Binocular Telescope (LBT) and will make use of multi-conjugated adaptive optics (MCAO) with two 349 actuators deformable mirrors (DM), two 672 actuator deformable secondary mirrors and a total of 4 wavefront sensors (WFS) by using 8 or 12 natural guide stars each. The goal of the MCAO is to increase sky coverage and achieve a medium Strehl-ratio over the 2 arcmin field of view. To test the concepts and prototypes, a laboratory setup of one MCAO arm is being built. We present the layout of the MCAO prototype, planned and accomplished tests, especially for the used Xinetics DMs, and a possible setup for a test on sky with an existing 8m class telescope.

We present a 1:3 scale model of the LINC-NIRVANA interferometer. This laboratory Fizeau, or image plane, interferometer allows us to test many aspects of LINC-NIRVANA before the final instrument is integrated. We have used this testbed interferometer to practice alignment procedures, verify the optical design, show that point spread functions with low (10\%) Strehl ratio can maintain high fringe contrast, and test the fringe tracking algorithm by running the interferometer in a closed piston loop.

We test the statistical properties of static, atmospherelike wave fronts in glass that allow repeatable testing of astronomical adaptive optics instrumentation. The technology is mask-structured ion exchange (MSI) in glass and has significant advantages over other transmissive technologies. The screens are easy to clean, are insensitive to ambient temperature changes, and have high optical-to-near-infrared transmission. However, the effective coherence length (r0) on each of the fabricated screens is systematically too large or, equivalently, the fabricated aberrations are too weak. Despite this strong caveat, the screens appear to be quite useful: Long-exposure point-spread functions have realistic shapes, and power spectrum indices closely match those of the computer-generated wave fronts. Most significant, stacking screens with similar r0 values reduced r0 by the amount predicted by turbulence theory. The refractivity of MSI screens remains unmeasured. Finally, we present our design of an optical system that emulates the key characteristics of the Very Large Telescope, made to contain glass phase screens and to mimic an array of stars for multiconjugate adaptive optics system testing.

We describe Algorithms for Calibration, Optimized Registration, and Nulling the Star in Angular Differential Imaging (ACORNS-ADI), a new, parallelized software package to reduce high-contrast imaging data, and its application to data from the SEEDS survey. We implement several new algorithms, including a method to register saturated images, a trimmed mean for combining an image sequence that reduces noise by up to ~20%, and a robust and computationally fast method to compute the sensitivity of a high-contrast observation everywhere on the field-of-view without introducing artificial sources. We also include a description of image processing steps to remove electronic artifacts specific to Hawaii2-RG detectors like the one used for SEEDS, and a detailed analysis of the Locally Optimized Combination of Images (LOCI) algorithm commonly used to reduce high-contrast imaging data. ACORNS-ADI is written in python. It is efficient and open-source, and includes several optional features which may improve performance on data from other instruments. ACORNS-ADI requires minimal modification to reduce data from instruments other than HiCIAO. It is freely available for download at www.github.com/t-brandt/acorns-adi under a BSD license., Comment: 15 pages, 9 figures, accepted to ApJ. Replaced with accepted version; mostly minor changes. Software updated

In contrast to numerical methods for beam shaping, analytical beam shaping consists of two steps: first, finding a purely geometrical distortion between the input plane and the output plane redistributing the intensity of the incoming wave front; and, second, computing a phase-only element realizing this coordinate transform. For the latter the method of stationary phase may be applied. The known classes of possible analytical wave transformation are extended to comprise separable and isotropic super-Gaussian-to-super-Gaussian conversion as well as transformation of Gaussian arrays to super-Gaussian distributions, and vice versa. The resulting optical phase elements contain no spiral phase dislocation and may thus be realized as refractive or diffractive elements. In addition, the outgoing wave front does not contain spiral phase dislocations.

The upgrade of the VLTI infrastructure for the 2nd generation instruments is now complete with the transformation of the laboratory, and installation of star separators on both the 1.8-m Auxiliary Telescopes (ATs) and the 8-m Unit Telescopes (UTs). The Gravity fringe tracker has had a full semester of commissioning on the ATs, and a first look at the UTs. The CIAO infrared wavefront sensor is about to demonstrate its performance relative to the visible wavefront sensor MACAO. First astrometric measurements on the ATs and astrometric qualification of the UTs are on-going. Now is a good time to revisit the performance roadmap for VLTI that was initiated in 2014, which aimed at coherently driving the developments of the interferometer, and especially its performance, in support to the new generation of instruments: Gravity and MATISSE., 9 pages, 6 figures, 1 table, Proc. SPIE 2016