This PDF file contains the front matter associated with SPIE Proceedings Volume 11448, including the Title Page, Copyright information, and Table of Contents.

We present recent results obtained with the VLT/MUSE Integral Field Spectrograph fed by the 4LGSF and its laser tomography adaptive optics module GALACSI. While this so-called narrow-field mode of MUSE was not designed to perform directly imaging of exoplanets and outflows, we show that it can be a game changer to detect and characterize young exoplanets with a prominent emission lines (i.e Hα, tracer of accretion), at moderate contrasts. These performances are achieved thanks to the combo of a near-diffraction limited PSF and a medium resolution spectrograph and a cross-correlation approach in post-processing . We discuss this in the context of ground and space, infrared and visible wavelengths, preparing for missions like JWST and WFIRST in great synergy and as pathfinder for future ELT/GSMT (Extremely Large and/or Giant Segmented Mirror Telescopes) instruments.

Orbital parameters of stellar companions can be constrained by multi-epoch observations where the astrometric position relative to the host star is measured. Additionally, radial velocity (RV) measurements of the host star may constrain the companion mass. We describe two major advances for high contrast imaging systems that significantly improve estimation of orbital parameters and masses. First, well-calibrated fiducial satellite speckles are inserted in the science images by way of deformable mirror (DM) modulation to improve astrometric measurement accuracy. Second, radial velocity measurement of the companion light reveals its velocity along the line-of-sight. We describe how the two techniques, together, can efficiently constrain orbital parameters and masses, and can do so over a shorter observation time baseline than previously possible. We demonstrate our technique with the REACH (Rigorous Exoplanetary Atmosphere Characterization with High dispersion coronagraphy) instrument at the Subaru Telescope. REACH takes extreme adaptive optics corrected light via single mode fiber from the SCExAO instrument and injects it to the high-resolution (R<70000) infrared spectrograph IRD instrument. With this technique we can achieve an astrometric precision of 1.7 mas and simultaneously measure radial velocity to a precision of <2 m/s. This high precision technique can also be extended to determine the orbits and characterize young massive planets around M-type stars.

Determining the PSF remains a key challenge for post adaptive-optics (AO) observations regarding the spatial, temporal and spectral variabilities of the AO PSF, as well as itx complex structure. This paper aims to provide a non-exhaustive but classified list of techniques and references that address this issue of PSF determination, with a particular scope on PSF reconstruction, or more generally pupil-plane-based approaches. We have compiled a large amount of references to synthesize the main messages and kept them at a top level. We also present applications of PSF reconstruction/models to post-processing, more especially PSF-fitting and deconvolution for which there is a fast progress in the community.

PSF knowledge is central to extract science from observations with adaptive optics. However, it is often challenging to have a good PSF estimate. For instance, this is a problem for the integral field unit (IFU) OSIRIS at Keck Observatory. OSIRIS has a field of only few arcseconds, and it is often impossible to obtain a good empirical PSF. OSIRIS is equipped with an imager designed to track changes in the PSF on a reference star. However, the imager is 20 arcseconds away, which prevents to apply the observed PSF directly to spectroscopic data. We developed a new software package to predict PSF variability for Keck AO images (AIROPA, see Paolo Turri’s contribution, this conference). To properly use the parallel imager to predict a PSF on the IFU, we adapted the code to the OSIRIS case (AIROPA-IFU). Here, we present results of the application of this post-processing tools to Galactic Center observation. We also discuss the challenges encountered and the lessons learned when doing PSF

The Adaptive Optics Module of MAVIS is a self-contained MCAO module, which delivers a corrected FoV to the postfocal scientific instruments, in the visible. The module aims to exploit the full potential of the ESO VLT UT4 Adaptive Optics Facility, which is composed of the high spatial frequency deformable secondary mirror and the laser guide stars launching and control systems. During the MAVIS Phase A, we evaluated, with the support of simulations and analysis at different levels, the main terms of the error budgets aiming at estimating the realistic AOM performance. After introducing the current opto-mechanical design and AO scheme of the AOM, we here present the standard wavefront error budget and the other budgets, including manufacturing, alignment of the module, thermal behavior and noncommon path aberrations, together with the contribution of the upstream telescope system.

We present the status and plans for the Keck All sky Precision Adaptive optics (KAPA) program. KAPA includes four key science programs, an upgrade to the Keck I laser guide star (LGS) adaptive optics (AO) facility to improve image quality and sky coverage, AO telemetry based point spread function (PSF) estimates for all science exposures, and an educational component focused on broadening the participation of women and underrepresented groups in instrumentation. For the purpose of this conference we will focus on the AO facility upgrade which includes implementation of a new laser, wavefront sensor and real-time controller to support laser tomography, the laser tomography system itself, and modifications to an existing near-infrared tip-tilt sensor to support multiple natural guide star (NGS) and focus measurements.

The 4-meter Daniel K. Inouye Solar Telescope will be upgraded with multi-conjugate adaptive optics. Two high-altitude deformable mirrors shall be added, and a multi-directional wavefront sensor system and a real-time control computer cluster will replace the existing counterparts of the operational first-light, classical adaptive optics system in a few years. Herein we give a brief overview of the system. We present the current status of the project including the prototyping for the wavefront sensor system and the real-time control system.

Precise stellar photometry and astrometry require the best possible modelling of the point spread function (PSF). To date, the best performances have been obtained when building the PSF a posteriori, meaning directly from the image of dense stellar fields, by exploiting the fact that each star represents a different realisation of the same PSF. The recent advent of the Adaptive Optics technique makes this method more challenging, because of the strong PSF variations across the field of view. One alternative is to use a priori PSF-modelling techniques such as PSF-reconstruction (PSF-R), that rely on Adaptive Optics control loop data to determine the shape of the PSF at any spatial location. Despite being theoretically well established, so far a-priori methods have never surpassed the performance obtained by standard methods when applied to real astronomical imaging. Here we report on the successful use of PRIME, a new technique that combines both PSF-R and image fitting, to perform precise photometry and astrometry on real data of the Galactic globular cluster NGC6121, observed with SPHERE/ZIMPOL. Compared to the results obtained using standard techniques, PRIME achieves improvement in precision by up to a factor of four, and ensures a photometric accuracy within ∼ 0.1 mag. A similar performance is also achieved when using the analytical PSF method described by F´etick et al. 2019, which is specifically designed to model AO-assisted data. These results thus pave the way for the exploitation of innovative techniques to investigate resolved stellar population science cases with the new generation of Adaptive Optics-assisted instrumentation at the ESO’s Very Large Telescope, Keck or the Extremely Large Telescopes.

The Starfinder code has been one of the first attempts to face with the typical adaptive optics structured Point Spread Function (PSF) in dense star fields to accomplish astrometric and photometric analysis. The last release of the software can also handle a variation of the PSF across the Field of View (FoV). The PSF can be either extracted numerically from the brightest stars in the science field or computed externally and provided as an input in the form of a single image or a cube of images. This feature makes this software suitable to work with PSF models obtained by PSF reconstruction techniques. Starfinder also accepts as an input a user-defined parametric model and a variable pointing the PSF auxiliary data required by the parametric-model. This variable might containing also information about the spatial variation across the FoV. In this paper we describe the next release of Starfinder reporting also some examples and we give the recipe to use the tool for variable PSF.

Currently, two AO systems are operated at Subaru Telescope: AO188, which is a facility AO system, and SCExAO, which is a PI-type ExAO system operated behind AO188. In the next 5 year, large-scale upgrades are performed on AO188 for improving the AO performance and operation of AO188 and SCExAO and for the technical demonstration toward the future wide-field ULTIMATE-Subaru GLAO system at Subaru and an ExAO system at TMT, PSI. We are planning to upgrade the real-time control system, the LGS system, and bimorph DM. Also, a new NIR WFS, a LTAO WFS unit, and a beam-switching system will be installed into the Nasmyth IR platform. The installation of the LTAO WFS unit is a part of the ULTIMATE-START project, which implement a LTAO mode into AO188 and demonstrates technologies for the ULTIMATE-Subaru GLAO system. ULTIMATE-Subaru project aims at developing a next-generation, wide-field GLAO system and wide-field NIR instruments for Subaru Telescope, whose first light will be in FY2025.

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a high-contrast imaging system installed at the 8-m Subaru Telescope on Maunakea, Hawaii. Due to its unique evolving design, SCExAO is both an instrument open for use by the international scientific community, and a testbed validating new technologies, which are critical to future high-contrast imagers on Giant Segmented Mirror Telescopes (GSMTs). Through multiple international collaborations over the years, SCExAO was able to test the most advanced technologies in wavefront sensors, real-time control with GPUs, low-noise high frame rate detectors in the visible and infrared, starlight suppression techniques or photonics technologies. Tools and interfaces were put in place to encourage collaborators to implement their own hardware and algorithms, and test them on-site or remotely, in laboratory conditions or on-sky. We are now commissioning broadband coronagraphs, the Microwave Kinetic Inductance Detector (MKID) Exoplanet Camera (MEC) for high-speed speckle control, as well as a C-RED ONE camera for both polarization differential imaging and IR wavefront sensing. New wavefront control algorithms are also being tested, such as predictive control, multi-camera machine learning sensor fusion, and focal plane wavefront control. We present the status of the SCExAO instrument, with an emphasis on current collaborations and recent technology demonstrations. We also describe upgrades planned for the next few years, which will evolve SCExAO —and the whole suite of instruments on the IR Nasmyth platform of the Subaru Telescope— to become a system-level demonstrator of the Planetary Systems Imager (PSI), the high-contrast instrument for the Thirty Meter Telescope (TMT).

This paper discusses various practical problems arising in the design and simulation of predictive control methods for adaptive optics. Although there has been increased attention towards optimal prediction and control methods for AO systems, they are often tested in simplified simulation environments. The use of advanced AO simulators however, is a valuable alternative to the use of real data or laboratory experiments, as they provide both a flexible environment which is ideal for testing a new algorithm and are more accessible to non-experts. Topics that are often not explicitly discussed, such as the identification of a turbulence dynamics model from data, the use of matrix structures in AO systems to decrease the computational complexity and the implementation of Kalman filters to optimally deal with realistic noise conditions are examined. All topics discussed are illustrated by an accompanying Matlab code, which is based on the existing Matlab AO toolbox OOMAO.

Multiconjugate adaptive optics (MCAO) systems have the potential to deliver diffraction-limited images over much larger fields of view than traditional single conjugate adaptive optics systems. In MCAO, the high altitude deformable mirrors (DMs) cause a distortion of the pupil plane and lead to a dynamic misregistration between the DM actuators and the wavefront sensors (WFSs). The problem is much more acute for solar astronomy than for night-time observations due to the higher spatial sampling of the WFSs and DMs, and the fact that the science observations are often made through stronger turbulence and at lower elevations. The dynamic misregistration limits the quality of the correction provided by solar MCAO systems. In this paper, we present PropAO, the first AO simulation tool (to our knowledge) to model the effect of pupil distortion. It takes advantage of the Python implementation of the optical propagation library PROPER. PropAO uses Fresnel propagation to propagate the amplitude and phase of an incoming wave through the atmosphere and the MCAO system. The resulting wavefront is analyzed by the WFSs and also used to evaluate the corrected image quality. We are able to reproduce the problem of pupil distortion and test novel non-linear reconstruction strategies that take the distortion into account. PropAO is shown to be an essential tool to study the behavior of the wavefront reconstruction and control for the European Solar Telescope.

We demonstrate numerically the phasing of a telescope with a primary segmented mirror consisting of 800 hexagonal segments using a pyramid wavefront sensor, supported by experiments. The segments are initially misaligned in piston/tip/tilt with median inter-segment steps of several micrometers. We simulate a mirror with some missing segments and a telescope spider with large optical phase discontinuities across its six vanes. The physical optics simulation is validated by experiments on the LOOPS optical bench at LAM. The correct combination of step solutions is selected by maximum likelihood methods. We emulate different star magnitudes and seeing conditions.

The National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) achieved first light in late 2019. The DKIST’s design includes a wavefront correction system, which incorporates Adaptive Optics (AO) in order to feed a diffraction-limited beam to five of its first-light science instruments. The first-light DKIST AO is a single-conjugate system designed to achieve 0.3 Strehl at 500 nm observing wavelength in our expected median seeing of r0 = 7 cm. The system incorporates a 1600-actuator Deformable Mirror (DM), a fast tip-tilt (FTT) corrector, a low-latency hybrid Field Programmable Gate Array (FPGA) / Central Processing Unit (CPU) real-time controller, and a correlating Shack-Hartmann wavefront sensor with 1457 active subapertures. We present results from the first light campaign of the DKIST, focusing on AO system performance. We compare the on-sky AO performance to the performance predicted through error-budget analysis and discuss implications for ongoing operation of DKIST and the upgrade path to DKIST multi-conjugate AO.

Our past GAPplanetS survey over the last 5 years with the MagAO visible AO system discovered the first examples of accreting protoplanets (by direct observation of H-alpha emission). Examples include LkCa15 b (Sallum et al. 2015) and PDS70 b (Wagner et al. 2018). In this paper we review the science performance of the newly (Dec. 2019) commissioned MagAO-X extreme AO system. In particular, we use the vAPP coronagraphic contrasts measured during MagAO-X first light. We use the Massive Accreting Gap (MAG) protoplanet model of Close 2020 to predict the H-alpha contrasts of 19 of the best transitional disk systems (ages 1-5 Myr) for the direct detection of H-alpha from accretion of hydrogen onto these protoplanets. The MAG protoplanet model applied to the observed first light MagAO-X contrasts predict a maximum yield of 46±7 planets from 19 stars (42 of these planets would be new discoveries). This suggests that there is a large, yet, unexplored reservoir of protoplanets that can be discovered with an extreme AO coronagraphic survey of 19 of the best transitional disk systems. Based on our first light contrasts we predict a healthy yield of protoplanets from our MaxProtoPlanetS survey of 19 transitional disks with MagAO-X.

The Multi-Unit Spectroscopic Explorer instrument (MUSE), is an integral-field spectrograph at one of the Nasmyth foci of the 8m-class Yepun telescope at Paranal observatory. MUSE's most powerful modes use the Adaptive Optics Facility consisting of a Deformable Secondary Mirror with over 1000 actuators commanded by a real-time computer up to 1000 times per second. At the core of the system are 4 laser guide stars monitored by GALACSI, the wave-front sensor system. MUSE functions with two modes: Wide-Field Mode (1'x1' field), making use of Ground Layer Adaptive Optics and Narrow-Field Mode (7.5"x7.5" field) using full laser tomography. In this work, we will present the results of a campaign to monitor the AO performance as measured by MUSE during the first years of operations. We will evaluate the dependence of this performance, as characterized by the point-spread function, on easily monitored environmental parameters such as ground-layer fraction, coherence time, seeing, and airmass.

PALM-3000 (P3K), the second-generation adaptive optics (AO) instrument for the 5.1 meter Hale telescope at Palomar Observatory, underwent a significant upgrade to its wavefront sensor (WFS) arm and real-time control (RTC) system in late 2019. Main features of this upgrade include an EMCCD WFS camera capable of 3.5 kHz framerates and advanced Digital Signal Processor (DSP) boards to replace the aging GPU based real-time control system. With this upgrade P3K is able to maintain a lock on natural guide stars fainter than mV=16. Here we present the design and on-sky re-commissioning results of the upgraded system.

MAORY is a post-focal adaptive optics module that forms part of the first light instrument suite for the ELT. The main function of MAORY is to relay the light beam from the ELT focal plane to the client instrument while compensating the effects of the atmospheric turbulence and other disturbances affecting the wavefront from the scientific sources of interest.

The presence of a six legged 50cm-wide spider supporting the secondary mirror of the Extremely Large Telescope (ELT) breaks the spatial continuity of the incoming wave-front. Atmospheric turbulence, low wind effect and thermo-mechanical drift of the deformable mirror are all potential contributors to discontinuities between the six segments of the ELT pupil. It is therefore necessary to measure these differential pistons in order to reconstruct the full wave-front. The pyramid wave-front sensor is currently the preferred design for adaptive optics systems. However, it was shown to be a poor differential piston sensor in the visible, under partial turbulence correction, leading to a severe degradation of the image quality. Using the COMPASS adaptive optics (AO) simulator, we first investigate strategies to ensure the spatial continuity of the correction applied on the deformable mirror. These methods present some limitations in strong seeing conditions, when the corrugated phase varies a lot below the spider legs, and lead to a significant degradation of the Strehl Ratio. To tackle this critical issue, we propose as a second step to couple the continuity hypothesis with a petalometer: a sensor specifically designed for sensing the differential piston. As candidates, we compare an unmodulated pyramid, a Zernike wavefront-sensor and a Zernike coupled with a field stop. We present results regarding their sensitivity and their reliability when working in operation, in presence of realistic AO residuals.

Twenty years ago, the Altair RTC processed a set of gradients from a 12×12 grid of gradients into actuator commands for the 177 DM actuators using a single-threaded process to perform a matrix vector multiply (MVM). Now, twenty years later, NRC Herzberg is building Narrow Field Infrared Adaptive Optics System (NFIRAOS) for the Thirty Meter project, a multi-conjugate AO system consisting of six LGS WFS, one natural guide star pyramid WFS and two deformable mirrors. The NFIRAOS RTC converts gradients from six 60x60 gradient grids into commands for the approximately 7650 actuators of the two DMs. The NFIRAOS RTC MVM computation is several orders of magnitude larger than the Altair RTC and requires dozens of threads. This paper reports on a literature search of the current AO system specifications and future AO systems, and then discusses the Herzberg Extensible Adaptive Real-Time controller (HEART) toolkit which is being used for various future RTC’s. This will highlight some of the design challenges for different size projects and design considerations that have been taken into account during the build of HEART will also be highlighted.

With the upcoming giant class of telescopes, Adaptive Optics (AO) has become more essential than ever before to get access to the full potential offered by those telescopes. The complexity of such AO systems is reaching extreme heights, and disruptive developments will have to be made in order to build them. One of the critical component of a AO system is the Real Time Controller (RTC) which will have to compute the slopes and the Deformable Mirror (DM) commands at high frequency, in a range of 0.5 to several kHz. Since the complexity of the computations involved in the RTC is increasing with the size of the telescope, fulfilling RTC requirements for Extremely Large Telescope (ELT) class is a challenge. As an example, the MICADO SCAO (Single Conjugate Adaptive Optics) system requires around 1 TMAC/s for the RTC to get sufficient performance. This complexity brings the need for High Performance Computing (HPC) techniques and standards, such as the use of hardware accelerator like GPU. On top of that, building a RTC is often project-dependent as the components and the interfaces change from one instrument to an other. The COSMIC platforms aims at developing a common AO RTC platform which is meant to be powerful, modular and available to the AO community. This development is a joint effort between Observatoire de Paris and the Australian National University (ANU) in collaboration with the Subaru Telescope. We focus here on the current status of the core hard real-time component of this platform. The H-RTC pipeline is composed of Business Units (BU): each BU is an independent process in charge of one particular operation, such as Matrix Vector Multiply (MVM) or centroid computation, that can be made on CPU or on GPU. BUs read and write data on Shared Memory (SHM) handled by the CACAO framework. Synchronization between each BU can then be made either by using semaphore or by busy waiting on the GPU to ensure very low jitter. The RTC pipeline can then be controlled through a Python interface. One of the key point of this architecture is that the interfaces of a BU with the various SHM is abstracted, so adding a new BU in the collection of available ones is straight forward. This approach allows a high performance, scalable, modular and configurable RTC pipeline that could fit the needs of any AO system configuration. Performance has been measured on a MICADO SCAO scale RTC pipeline with around 25,000 slopes by 5,000 actuators on a DGX-1 system equipped with 8 Tesla V100 GPUs. The considered pipeline is composed of two BUs : the first one takes an input the raw pyramid WFS image (produced by simulator), applies on it dark and flat references, and then extract the useful pixel from the image. The second BU performs the MVM and the integration of the commands following a classical integrator command law. Synchronization between the BU is made through GPU busy waiting on the BU inputs. Performance obtained shows a mean latency up to 235 μs using 4 GPUs, with a jitter of 4.4 μs rms and a maximum jitter of 30 μs

We present new results with the Asymmetric Pupil vector-Apodizing Phase Plate (APvAPP), which combines coronagraphy and wavefront sensing to enable a 100% science duty cycle. We show on-sky results at SCExAO with a non-linear, model-based wavefront sensing algorithm improving the raw contrast by a factor of 2 at 2-4 lambda/D. We also report on the first on-sky demonstration of spatial Linear Dark Field Control with the APvAPP. Together, these algorithms improve the control speed, raw contrast gain and allow more modes to be corrected. Finally, we discuss the path towards coherent differential imaging with the APvAPP.

Point-diffraction interferometers are a class of wavefront sensors which can directly measure the phase with great accuracy, regardless of defects such as vortices and disconnected apertures. Due to these properties, they have been suggested in applications such as cophasing of telescope segments, wavefront sensing impervious to the island effect and high-contrast AO and imaging. This paper presents an implementation of this class of interferometer, the Calibration & Alignment~WFS (CAWS), and the results of the first on-sky tests in the visible behind the SCAO loop of the CANARY AO experiment at the William Herschel Telescope. An initial analysis of AO residuals is performed in order to retrieve the SNR of interference fringes and assess the instrument's performance under various observing conditions. Finally, these results are used to test the validity of our models, which would allow for rapid implementation-specific modelling to find minimum-useful flux and other CAWS limits.

We report on a test bed to compare the performance of three different wavefront sensors, the Shack-Hartmann Wavefront Sensor (SHWFS), the Pyramid Wavefront Sensor (PWFS), and the non-linear Curvature Wavefront Sensor (nlCWFS). No single wavefront sensor easily allows for sensing all aspects of atmospheric turbulence. For instance the SHWFS has a large dynamic range and a linear response to input phase aberrations but is not sensitive to low order modes. The PWFS uses the full spatial resolution of the pupil which gives it increased sensitivity to low order modes, however it still treads the line between achieving high dynamic range and high sensitivity. The nlCWFS is the only wavefront sensor designed to sense low and high, spatial frequencies, however this leads to a complex algorithm. We discuss the reconstruction algorithm for each WFS along with simulated comparisons, we present the optical design for the WFS comparison tes tbed, and outline the adaptive optics controls system.

By now Adaptive optics systems are used at nearly all large telescopes. Over the past years not only the number of applications increased but as well the correction order and specialization have evolved. One key element following and sometimes driving the development of adaptive optics is the wavefront corrector. The construction and development of the ELTs and other new facilities pushed the development of new and much larger deformable mirrors. An overview of the available and newly developed technologies with their key performances is presented.

The SAM616 is a prototype deformable mirror built by CILAS for the Thirty Meter Telescope’s Narrow Field Infrared Adaptive Optics System (NFIRAOS). It was delivered to NRC-HAA in August 2018 for performance testing at room temperature and at the operating temperature of NFIRAOS, -30oC. Properties that were measured include the total stroke, hysteresis, creep and coupling of the actuators, as well as the flattening ability at various temperatures. The mirror has been found to meet (and in some case exceed) all its performance requirements including its flattening requirements.

We are developing a new adaptive secondary mirror (ASM) for the University of Hawaii 2.2-meter telescope based on a novel and very efficient hybrid variable reluctance actuator developed by TNO. The actuator technology has broad implications on the ASM design and results in an ASM with a thicker facesheet, lower power dissipation, and simple controls. We report here preparations and plans for lab testing as well as on-sky demonstration of the ASM. The lab calibrations of the ASM influence functions will use a phase measuring deflectometry setup. The on-sky tests will include the evaluation of the use of the ASM for narrow field AO observations at visible through near infrared wavelengths, for very wide fields of view ground-layer adaptive optics, and for seeing limited non-adaptive optics observations.

High-contrast imaging instruments are today primarily limited by non-common path aberrations appearing between the wavefront sensor of the adaptive optics system and the science camera. Early attempts at using artificial neural networks for focal-plane wavefront sensing showed some successful results but today's higher computational power and deep architectures promise increased performance, flexibility and robustness that have yet to be exploited. We implement two convolutional neural networks to estimate wavefront errors from simulated point-spread functions. We notably train mixture density models and show that they can assess the ambiguity on the phase sign by predicting each Zernike coefficient as a probability distribution. Our method is also applied with the Vector Vortex coronagraph (VVC), comparing the phase retrieval performance with classical imaging. Finally, preliminary results indicate that the VVC combined with polarized light can lift the sign ambiguity.

This paper shows that a simple convolutional neural network (CNN) can be used to build an object-agnostic wavefront sensor. Using the well-known Phase Diversity approach as a point of departure, Fourier-space metrics are computed from the conventional and diversity images and then fed to the CNN, which predicts values of the underlying Zernike coefficients. The methodology is shown to work in the presence of Gaussian noise. Prediction errors for defocus, astigmatism, and spherical are on the order of 1/100 of the wavelength.

In this contribution we apply to Paranal a technique successfully tested and implemented in the ALTA Center to support LBT observations permitting us to provide optical turbulence forecasts at time scales of 1 and 2 hours with unprecedent accuracies and with important gain with respect to the forecasts done with simple real-time measurements (method by persistence). We use an autoregressive method that takes into account real-time measurements and forecast performed with a mesoscale atmospherical model. Results obtained so far give an RMSE of 0.1” at 1h for the seeing and a probability to detect the seeing weaker than the first tertile (calculated on climatological scale) equal to 98%. In this study we extend the techniques to other astroclimatic parameters beside the seeing.

Optical turbulence affects significantly the quality of ground-based astronomical observations. An accurate and reliable forecast of optical turbulence can help to optimize the scheduling of the science observations and to improve both the quality of the data and the scientific productivity of the observatory. However, forecasts of the turbulence to a level of accuracy which is useful in the operations of large observatories are notoriously difficult to obtain. Several routes have been investigated, from detailed physical modelling of the atmosphere to empirical data-driven approaches. Here, we present an empirical approach exploiting spatial diversity and based on simultaneous measurements between two nearby sites, Cerro Paranal, host of the Very Large Telescope (VLT), and Cerro Armazones, future host of the Extremely Large Telescope (ELT) in Chile. We study the correlation between the high-altitude turbulence as measured between those two sites. This is part of the on-going efforts initiated by the European Southern Observatory (ESO), to obtain short-term forecasts of the turbulence to facilitate the operations of the VLT and prepare the ELT mode of operations.

Adaptive optics (AO) techniques like laser tomography adaptive optics (LTAO) and multi-conjugated adaptive optics (MCAO) are becoming more and more used in the development of instrumentation for the existing 8-m class telescopes and future extremely large telescopes (ELT). Achieving the required level of AO correction over wide field of view requires the knowledge of the turbulence strength vs the altitude, first during the design phase of the instruments to ensure they match the needed performances, and then during the on-sky operation to optimize the AO control according to the atmospheric conditions. Obtaining reliable measurements of the turbulence in three dimensions is thus of high importance, today and in the future. The Paranal Observatory gives access to three atmosphere profilers and one atmosphere monitor on one single site. The possibility to obtain simultaneous data on independent systems is a great opportunity to compare their results and evaluate the advantages of each method. We present the results of statistical analysis of data coming from these systems, obtained in different periods and with various atmosphere conditions. From this analysis, we can draw conclusions on conditions needed for a useful comparison of the profilers and show the possible needed attempt to be made on aligning their assumptions and thus the provided parameters.

We are upgrading and refurbishing the first-generation adaptive-secondary mirror (ASM)-based AO system on the 6.5-m MMT in Arizona, in an NSF MSIP-funded program that will create a unique facility specialized for exoplanet characterization. This update includes a third-generation ASM with embedded electronics for low power consumption, two pyramid wavefront sensors (optical and near-IR), and an upgraded ARIES science camera for high-resolution spectroscopy (HRS) from 1-5 μm and MMT-POL science camera for sensitive polarization mapping. Digital electronics have been incorporated into each of the 336 actuators, simplifying hub-level electronics and reducing the total power to 300 W, down from 1800 W in the legacy system — reducing cooling requirements from active coolant to passive ambient cooling. An improved internal control law allows for electronic damping and a faster response. The dual pyramid wavefront sensors allow for a choice between optical or IR wavefront sensing depending on guide star magnitude, color, and extinction. The HRS upgrade to ARIES enables crosscorrelation of molecular templates to extract atmospheric parameters of exoplanets. The combination of these upgrades creates a workhorse instrument for exoplanet characterization via AO and HRS to separate planets from their host stars, with broad wavelength coverage and polarization to probe a range of molecular species in exoplanet atmospheres.

SHARK-NIR in an instrument that will provide direct imaging, coronagraphic imaging, dual band imaging and low resolution spectroscopy in Y, J and H bands, and it will be soon installed at the Large Binocular Telescope. Used in combination with SHARK-VIS (operating in V band) and LMIRCam of LBTI (operating from K to M bands), SHARKNIR will exploit coronagraphic simultaneous observations in three different wavelengths. Exoplanets search and characterization, young stellar systems, jets and disks are the main science cases, but the extreme performance of the LBT AO systems, above all in the faint end regime, will allow to open to science difficult to be achieved from other similar instruments, such as AGN and QSO morphological studies. A variety of coronagraphic techniques have been implemented, as the Gaussian Lyot, Shaped Pupil and Four Quadrant masks, with the aim to possibly have a suitable coronagraphic masks for each science case, since the coronagraphic requirement in term of contrast and inner and outer working angle are depending on the target and on the science to be achieved. We report here about the SHARK-NIR status, that should be installed at LBT in mid-2021

ULTIMATE-Subaru Tomography Adaptive optics Research experimenT (ULTIMATE-START) is a laser tomography AO project on the Subaru telescope. The project is planned to achieve high Strehl Ratio AO correction in NIR bands, and moderate AO correction in visible bands above 600nm. An asterism of 4 laser guide stars (LGSs) will be launched from the laser launching telescope behind the secondary mirror. The tomography wavefront sensing unit with four 32$times$32 Shack-Hartmann wavefront sensors will be installed behind the current facility LGS AO system, AO188. The deformable mirror of AO188 will be upgraded to a 64$times$64 element DM. The corrected light will be fed to the optical integral field spectrograph, 3DII, and NIR camera and spectrograph, IRCS, through a beam switching optics for IR-side Nasmyth focus instruments under development. The first light of the laser launching system and wavefront sensing unit is planned in 2021.

This paper presents the specifications of TROIA - TuRkish adaptive Optics system for Infrared Astronomy system, the science rationale for these specifications, and description of the site technical and environmental conditions to be taken into account in the adaptive optics (AO) system design for the Eastern Anatolia Observatory - DAG telescope. With it’s 468 actuators, EMCCD camera, and the pyramid wavefront sensor configuration; TROIA is able to adapt the degree of correction to a given guide star (GS) brightness during observations. The high actuator density of TROIA AO system will allow DAG to perform astronomical observations at ExAO performances.

The wavefront reconstruction with interaction matrix composed of high-order Zernike polynomials as basis may be unintendedly less accurate when the wavefront manipulator of huge number of elements such as Microelectromechanical systems (MEMS) mirrors and Liquid Crystal on Silicon (LCOS) is used. One of the reasons of the lack of the accuracy in reconstruction comes from the mismatch between the rectangular elements of the LCOS in the orthogonal arrangement and the projected patterns obtained by the Zernike polynomials defined in the polar coordinates. To improve the accuracy of the wavefront reconstruction by the LCOS, the use of the random phase patterns is proposed with presumption to be appropriate for the orthogonally arranged high number of elements. The residual fitting errors of reconstructed wavefront are evaluated by numerical simulation to show the potential of the use of the random phase patterns instead of the use of the Zernike polynomials. It is found by the Monte-Carlo simulation of the Kolmogorov model that the more random phase patterns one uses, the more accurate one achieves to reconstruct the wavefront compared to the use of the Zernike patterns. Additionally, the comparison of the Strehl ratio of the AO system obtained with the Zernike patterns and that of the random patterns is performed.

Within the next decade the Extremely Large Telescopes [ELTs] with diameters up to 40m will see first light. To optimize a high contrast pyramid wavefront sensor for an ELT extreme adaptive optics system, we are developing the theoretical framework of a three-sided pyramid wavefront sensor (3PWFS). The 3PWFS should have a higher photon efficiency and therefore be more sensitive to wavefront aberrations than the traditional four-sided pyramid wavefront sensor (4PWFS) in the presence of noise. In this paper we present results from end-to-end simulations, and from test benches at the Laboratoire d’Astrophysique de Marseille, and the University of Arizona.

The new generation of ground-based extremely large telescopes rely on adaptive optics (AO). Many AO systems require the reconstruction of the turbulence profile, which is called atmospheric tomography. Due to the growth of telescope sizes the computational load for this problem is increasing drastically. Thus, the collaboration of state-of-the-art real-time hardware with an efficient solver that take advantage of the available hardware resources is of great importance. In this talk, we look at an iterative approach called FEWHA and its adaption to perform best on real-time hardware. We conclude our talk with a comparison between FEWHA and the frequently used MVM within the framework of MAORY.

Laser guide stars (LGS) are used in many adaptive optics systems to extend sky coverage. The most common wavefront sensor used in combination with a LGS is a Shack-Hartmann wavefront sensor (SHWFS). The ShackHartmann has a major disadvantage for extended source wavefront sensing because it directly samples the image. In this proceeding we propose to use the generalized-Optical Differentation Wavefront Sensor (g-ODWFS) a wavefront sensor for wavefront sensing of LGS. The g-ODWFS uses only 4 pixels per sub-aperture, has little to no aliasing noise and therefore no spurious low-order errors and has no need for centroid gain calibrations. In this proceeding we show the results of simulations that compare the g-ODWFS with the SHWFS.

The Mount Stromlo LGS facility includes two laser systems: a fiber-based sum-frequency laser designed and built by EOS Space Systems in Australia, and a Semiconductor Guidestar Laser designed and built by Aret´e Associates in the USA under contract with the Australian National University. The Beam Transfer Optics (BTO) enable either simultaneous or separate propagation of the two lasers to create a single LGS on the sky. This paper provides an overview of the Mount Stromlo LGS facility design, integration and testing of the two sodium guidestar lasers in the laboratory and on the EOS 1.8m telescope.

It is well known that Adaptive Optics (AO) observations do require the availability of natural stars (beside laser guide stars - LGSs) to obtain the tip-tilt and focus information of the atmospheric turbulence. Bright natural stars are not always available imposing the ultimate limit to the AO technology due to the small technical field planned for 40m range telescopes. The use of multiple LGSs, with their respective wavefront sensors and tomographic computations, requires the proper reconstruction of the turbulence column adding significant complexity and cost to the Adaptive Optics systems. Precise knowledge of the tip-tilt information is extremely useful for the accurate pointing of lasers in groundto-space optical communications and in space situational awareness applications. In these contexts the tip-tilt information cannot be obtained from natural stars. Our group have proposed an alternative way of measuring all relevant values of the atmospheric turbulence, specifically including tip-tilt, focus and also higher order aberrations, and tomographic information based on the use of the foreseen density anisotropies in the sodium layer. Results of an analysis using the available information about sodium layer profiles will be presented, showing up to what point anisotropies with the proper spatial and time scales could be expected. The requirements of a laser launch system capable of illuminating uniformly the metapupil at the height of the Na layer are identified and special attention is paid to the required laser power. The extended object generated at the Na-Layer should then be analysed with a wavefront sensor suited to that characteristic. The plenoptic camera is the potential candidate under study in this paper.

Stereo scintillation detection and ranging (S-SCIDAR) is a development of the well-established SCIDAR turbulence profiling technique. An S-SCIDAR instrument has been installed at the focus of one of the 1.8m Auxiliary Telescopes at Paranal observatory since April 2016. We discuss the limitations imposed by the Paranal S-SCIDAR instrument’s finite pixel size and exposure time. We present Monte Carlo simulation results quantifying the errors due to finite spatial and temporal sampling. We have reprocessed the existing S-SCIDAR dataset to compensate for these error sources; we discuss the impact of these corrections on the measured turbulence statistics.

The performance of tomographic adaptive optics systems will depend on the vertical profile of turbulence in the atmosphere. Since the profile is changing over time, to maintain optimal correction the tomographic reconstructor must be continually updated with new profile information. Several reconstructor parameters must then be chosen to optimise performance given the constraints of real-time computing resources: the number of reconstructed layers, reoptimisation period and averaging time. We analyse the effect of changing these parameters by coupling fast Fourier-domain AO simulation with a large database of over 10,000 high resolution turbulence profiles measured by the Stereo-SCIDAR at Paranal.

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) serves both a science instrument in operation, and a prototyping platform for integrating and validating advanced wavefront control techniques. It provides a modular hardware and software environment optimized for flexible prototyping, reducing the time from concept formulation to on-sky operation and validation. This approach also enables external research group to deploy and test new hardware and algorithms. The hardware architecture allows for multiple subsystems to run concurrently, sharing starlight by means of dichroics. The multiplexing lends itself to running parallel experiments simultaneously, and developing sensor fusion approaches for increased wavefront sensing sensitivity and reliability. Thanks to a modular realtime control software architecture designed around the CACAO package, users can deploy WFS/C routines with full low-latency access to all cameras data streams. Algorithms can easily be shared with other cacao-based AO systems at Magellan (MagAO-X) and Keck. We highlight recent achievements and ongoing activities that are particularly relevant to the development of high contrast imaging instruments for future large ground-based telescopes (ELT, TMT, GMT) and space telescopes (HabEx, LUVOIR). These include predictive control and sensor fusion, PSF reconstruction from AO telemetry, integrated coronagraph/WFS development, focal plane speckle control with photon counting MKIDS camera, and fiber interferometry. We also describe upcoming upgrades to the WFS/C architecture: a new 64x64 actuator first stage DM, deployment of a beam switcher for concurrent operation of SCExAO with other science instruments, and the ULTIMATE upgrade including deployment of multiple LGS WFSs and an adaptive secondary mirror.

The Facility AO systems at the LBT are based around the two Adaptive Secondary Mirrors (ASM) and the Pyramid Wavefront Sensors (PWFS), the latter being recently upgraded as part of the SOUL project in order to provide improved image quality performance and greater faint target sensitivity, at the LUCI and LBTI ports. These represent operational AO Systems with unique challenges for maintaining their optimal operational status. Based on our experience, especially over the last seven years, we present our approach to provide the readiness of the AO systems at all times including routine calibration, monitoring, and maintenance activities necessary to keep their performance at an optimal level. We also address intervention activities to improve the ASMs’ reliability and robustness.

Focal plane wavefront sensing and control has been identified as a crucial technology to enable high contrast imaging down to terrestrial mass, habitable zone exoplanets with future observatories. However, open questions remain as to how such algorithms should be integrated into existing systems to enable reaching their optimal performance, particularly for ground-based adaptive optics (AO). In this paper we use numerical simulations to show that a focal plane wavefront sensing and control technique running on millisecond timescales, called the Fast Atmospheric Self-coherent camera Technique (FAST), can be designed to operate as a “second stage” AO wavefront sensor (WFS), both for low and high order active wavefront control. Accordingly, we propose a closed-loop real-time controller architecture to use both an AO and FAST WFS to control a common DM.

The Mid-infrared ELT Imager and Spectrograph (METIS) enables high-resolution spectroscopic and coronagraphic imaging in the wavelength range 3 . . . 13 μm. To obtain diffraction-limited measurements, METIS uses a single conjugate adaptive optics (SCAO) system comprising the deformable mirror M4, the tip-tilt mirror M5, and an infrared pyramid wavefront sensor. Due the non-negligible spatio-temporal dynamics and the redundant tip-tilt corrections of M4 and M5, the development of suitable SCAO controllers for METIS is nontrivial. Therefore, we present an advanced model-based SCAO controller. This controller is based on the mechanical modes of the correcting mirrors and considers stroke constraints of the mirrors to prevent windup phenomena. Moreover, the presented controller is fully compatible with the latest Instrument-ELT-Interface and offers several advantages, such as: it can be easily reconfigured to compensate faulty mirror actuators; its controller design can be fully customized to the dynamics of the correcting mirrors. Furthermore, the proposed control concept promises an advanced wavefront correction despite the challenging characteristics of the METIS-SCAO system. Finally, we investigate the presented controller by end-to-end simulations.

In this paper, we develop an identification technique based on continuous-time Kautz basis functions and Maximum Likelihood estimation from discrete-time data to obtain a continuous-time model of a laboratory adaptive optics system. We illustrate the proposed identification method using synthetic data and experimental data of a laboratory adaptive optics setup. Finally we utilize the estimated model to develop a Model Predictive Control strategy that considers the deformable mirror actuation constraints. We illustrate the benefits of the model predictive control strategy via simulations and compare it against the classical Proportional-Integral controller.

The Learn and Apply reconstruction scheme uses the knowledge of atmospheric turbulence to generate a tomographic reconstructor, and its performance is enhanced by the real-time identification of the atmosphere and the wind profile. In this paper we propose a turbulence profiling method that is driven by the atmospheric model. The vertical intensity distribution of turbulence, wind speed and wind direction can be simultaneously estimated from the Laser Guide Star measurements. We introduce the implementation of such a method on a GPU accelerated non-linear least-squares solver, which significantly increases the computation efficiency. Finally, we present simulation results to demonstrate the convergence quality from numerically generated telemetry, the end-to-end Adaptive Optics simulation results, and a time-to-solution analysis, all based on the MAVIS system design.

Adaptive optics (AO) systems correct atmospheric turbulence in real time and they are normally used in large and medium telescopes but not in modest telescopes due to their size and cost. Here we propose a portable AO instrument capable of being installed in different medium and small-sized telescopes. The novelty of this new instrument is that it is based on the modularization of its components: simulator/calibrator, Wavefront Corrector (WFC) with a deformable mirror (DM) and Wavefront sensor (WFS) modules. This modular concept allows great flexibility in the design, being possible to easily adapt the instrument to the working telescope or instrument by adjusting each module independently. This concept also makes possible the comparison between different types of WFS such as Shack-Hartmann (S-H), Two Pupil Plane Position (TP3) or Pyramidal. Here we present the optical design and expected performance of the three WFS for 1.52m, Carlos Sanchez Telescope (TCS), and the preliminary results of the S-H sensor in laboratory and the first on-sky test.

During its move from the mountaintop of Cerro Pachon in Chile to the peak of Mauna Kea in Hawaii, the Gemini Planet Imager will receive various upgrades, including a pyramid wavefront sensor. As a non-linear sensor, a standard approach to linearize the response of the pyramid is induce a rapid circular modulation of the beam around the pyramid tip, trading off sensitivity for robustness during high turbulence. Using high temporal resolution Fourier Optics based simulations, we investigate phase reconstruction approaches that attempt to optimize the performance of the sensor with a dynamically adjustable modulation parameter. We have studied the linearity and gain stability of the sensor under different modulation and seeing conditions, and the ability of the sensor to correct non-common-path errors. We will also show performance estimates which includes a comparative analysis of the atmospheric columns above the two mountains, as well as the Error Transfer Function of the two systems.

We present the design, implementation and results of a full end-to-end simulation of the Gemini MCAO system, GeMS, using the AO simulation package DASP coupled with the AO RTC software package DARC. The multi-threaded and tuned performance of DASP can give close to real-time AO simulation of a GeMS system for rapid investigation of different combinations of AO control techniques and different atmospheric conditions. We demonstrate a full simulation of the current GeMS reconstruction technique and study the effect of applying different reconstruction algorithms for the purpose of prototyping potential control strategies for a generic future MCAO system.

Gemini Observatory currently has two operational adaptive optics systems, MCAO with GeMS on Gemini South and SCAO with ALTAIR on Gemini North, and plans to host multiple new AO systems in the coming years including the in-development MCAO system GNAO. With the great advances in CPU technology over the last decade, CPUs have become a viable platform for AO RTCs for large telescopes including current 8-m class telescopes and future Extremely Large Telescopes. This has opened up new opportunities to develop adaptive optics real time control systems using common CPU platforms and operating systems, providing simplified development paths and increased maintainability. Gemini plans to provide a CPU based AO RTC that can be feasibly used to upgrade the RTCs of both GeMS and ALTAIR and also provide an adaptable platform for future Gemini AO systems. To this end, a feasibility study was undertaken to asses the suitability of the open source DARC RTC software as a baseline for the Gemini AO systems. The results of this study were used to influence the procurement of an externally developed CPU-based RTC to provide for current and in-development Gemini AO systems and to act as a template for future systems.

The Learn and Apply tomographic reconstructor coupled with the pseudo open-loop control scheme shows promising results in simulation for multi-conjugate adaptive optics systems. We motivate, derive, and demonstrate the inclusion of a predictive step in the Learn and Apply tomographic reconstructor based on frozen-flow turbulence assumption. The addition of this predictive step provides an additional gain in performance, especially at larger wave-front sensor exposure periods, with no increase of online computational burden. We provide results using end-to-end numerical simulations for a multi-conjugate adaptive optics system for an 8m telescope based on the MAVIS system design.

To provide data sharper than JWST and deeper than HST, MAVIS (the MCAO Assisted Visible Imager and Spectrograph) will be driven by a state-of-the-art real-time control (RTC) system leveraging cutting edge technologies both in terms of hardware and software. As an implementation of the COSMIC platform, the MAVIS RTC will host a hard RTC module, fed in quasi real-time with optimized parameters from its companion soft RTC. In order to meet the AO performance requirement in the visible, the overall real-time pipeline latency should be in the range of few hundreds microseconds ; and, considering the several high order wavefront sensors (WFS) of the current optical design, the specifications of the hard RTC module are very close to those contemplated for ELT first light SCAO systems, making it as an at scale pathfinder for these future facilities. In this paper, we will review the hardware and software design and prototyping activities led during phase A of the project.

The Compute and control for adaptive optics (Cacao) is an open source software package providing a flexible framework for deploying real-time adaptive optics control. Cacao leverages CPU and GPU computational resources to meet the demands of modern AO systems with thousands of degrees of freedom running at kHz speed or faster. Cacao adopts a modular approach, where individual processes operate over a standardized data stream stucture. Advanced control loops integrating multiple sensors and DMs are built by assembling multiple such processes. High-level constructs are provided for sensor fusion, where multiple sensors can drive a single physical DM. The common data stream format is at the heart of Cacao, holding data content in shared memory and timing information as semaphores. Cacao is currently in operation on the general-purpose Subaru AO188 system, the SCExAO and MagAOX extreme-AO instruments. Its data stream format has been adopted at Keck, within the COMPASS AO simulation tool, and in the COSMIC modular RTC platform. We describe Cacao’s software architecture and toolset, and provide simple examples for users to build a real-time control loop. Advanced features are discussed, including on-sky results and experience with predictive control and sensor fusion. Future development plans will include leveraging machine learning algorithms for real-time PSF calibration and more optimal AO control, for which early on-sky demonstration will be presented.

W. M. Keck Observatory (WMKO) has granted in 2018 to Microgate, supported by Swinburne University and Australian National University, the contract for the design, implementation and test of the new Adaptive Optics Real Time Controller. The new system is going to replace the existing Keck Next Generation Wavefront Controller (NGWFC), delivered by the same company 14 years ago and still operational. The new RTC supports, on a smaller scale, most of the operating modii that are planned for the next generation of ELT RTCs, including laser tomography. In addition, the system needs to be interfaced to several wavefront cameras and mirrors, with heterogeneous interfaces. On that base, the system needs to conjugate several aspects, including flexible interfacing, computational throughput with low latency and minimum jitter, large telemetry storage capacity with fast querying capacity, easiness of maintainability, expandability, extreme reliability and environmental challenges to operate at 4,200 meters above the sea level. The proposed architecture comprehends an interface module, physically located close to the various sensors and mirrors, a computational unit based on GPUs and a storage server. The software implementation is based on a modular concept that starts from the COMPASS framework, developed at Observatoire de Paris, and supports easy expandability. The project implementation is almost completed and deployment to the telescope is planned for Q1/2021.

The Multi-conjugate Adaptive Optics RelaY (MAORY) should provide 30% SR in K band (50% goal) on half of the sky at the South Galactic Pole. Assessing its performance and the sensitivity to parameter variations during the design phase is a fundamental step for the engineering of such a complex system. This step, centered on numerical simulations, is the connection between the performance requirements and the Adaptive Optics system configuration. In this work we present MAORY configuration and performance and we justify the Adaptive Optics system design choices.

The Adaptive Optics (AO) performance significantly depends on the available Natural Guide Stars (NGSs) and a wide range of atmospheric conditions (seeing, Cn2, windspeed, . . . ). In order to be able to easily predict the AO performance, we have developed a fast algorithm - called TIPTOP - producing the expected AO Point Spread Function (PSF) for any of the existing AO observing modes (SCAO, LTAO, MCAO, GLAO), and any atmospheric conditions. This TIPTOP tool takes its roots in an analytical approach, where the simulations are done in the Fourier domain. This allows to reach a very fast computation time (few seconds per PSF), and efficiently explore the wide parameter space. TIPTOP has been developed in Python, taking advantage of previous work developed in different languages, and unifying them in a single framework. The TIPTOP app is available on GitHub at: https://github.com/FabioRossiArcetri/TIPTOP, and will serve as one of the bricks for the ELT Exposure Time Calculator.

The ESO ELT is expected to come into operation in 2025 and it will be the largest optical telescope in the world. Its performance relies heavily on Adaptive Optics (AO) systems including the integrated adaptive M4 mirror in the ELT and post focus MAORY system featuring an additional two adaptive mirrors. A performance verification unit (aka ’Test Unit’ (TU) is conceived to test the MAORY functionality prior its installation on the telescope. The TU requirements and the solution to emulate natural and laser guide stars, atmospheric turbulence and partial correction by the telescope M4 are described.

MAORY is the MCAO module for the ELT. It feeds MICADO and a still to be defined second port instrument. The ”Science Operation” Working Group of MAORY focuses the activity on the simulation of the science cases proposed for the instrument, deriving in this way the achievable performance in different observing conditions, as can be the case of a crowded globular cluster or an almost star-empty frame on a high-z target. In this paper, we discuss the recent activities of the WP focusing on the numerical simulations environment we built and on the contribution to the Operational Concept Description of MAORY.

The Giant Magellan Telescope design consists of seven circular 8.4 m diameter mirrors, together forming a single 24.5 m diameter primary mirror. This large aperture and collecting area can help extreme adaptive optics systems such as GMagAOX achieve the small angular resolutions and contrasts required to image habitable zone earth-like planets around late type stars and possibly lead to the discovery of life outside of our solar system. However, the GMT mirror segments are separated by large ⪆ 30 cm gaps, creating the possibility of fluctuations in optical path differences (piston) due to flexure, wind loading, temperature effects, and atmospheric seeing. In order to utilize the full diffraction-limited aperture of the GMT for high-contrast imaging, the seven mirror segments must be co-phased to well within a fraction of a wavelength. The current design of the GMT involves seven adaptive secondary mirrors, a dispersed fringe sensor (part of the AGWS), and a pyramid wavefront sensor (NGWS) to measure and correct the total path length between segment pairs, but these methods have yet to be tested “end-to-end” in a lab environment. We present the design and prototype of a “GMT High-Contrast Phasing Testbed” which leverages the existing MagAO-X ExAO instrument to demonstrate fine phase sensing and simultaneous AO-control for high-contrast GMT natural guide star science. The testbed will simulate the GMT primary and secondary mirror phasing system. It will also simulate the future GMT ExAO instrument’s (GMagAO-X) “parallel DM” tweeter concept of splitting up the GMT pupil onto several commercial DMs using a reflective hexagonal pyramid. A dispersed fringe sensor will also be implemented into the testbed for coarse piston phase-sensing along with MagAO-X’s pyramid wavefront sensor to measure and correct the fine phasing level of the GMT primary mirror segments under realistic wind load and seeing conditions.

The first light instrument on the Thirty Meter Telescope (TMT) project will be the InfraRed Imaging Spectrograph (IRIS). The IRIS On-Instrument Wavefront Sensor (OIWFS) provides diffraction limited wavefront sensing – in both tip/tilt and tip/tilt/focus modes – to NFIRAOS (Narrow Field InfraRed Adaptive Optics System). As part of the final design phase, we have further developed the optical and mechanical designs. We present recent changes to the optical design and the resulting performance and tolerance analysis. Changes include decreasing the field of view to 1.5×1.5 arcseconds (square) and moving the field lens to reduce vignetting of the science image. The mechanical design is being updated with more detail for the optical mounts. We present here example mounts and associated analyses and our plans for future prototyping.

MAORY (Multi-conjugate Adaptive Optics RelaY) is one of the first light instruments for the ESO Extremely Large Telescope (ELT). It will be firstly used by MICADO (Multi-AO Imaging CamerA for Deep Observations), a near-infrared high-angular resolution imager, to compensate aberrations and provide highStrehl images within a 53”×53” Field of View (FoV). The complexity of MAORY requires calibration functionalities for both the AIV (Assembly-Integration-Verification) and the operational phase. The Calibration Unit (CU), providing suitable light sources, both Natural Guide Stars (NGS) and Laser Guide Stars (LGS), will enable MAORY to run calibration templates as well as verification and test procedures, in standalone mode, drastically reducing the amount of required night-time for such operations. An overview of the instrument, the current status of the design and the main challenges to face in the future are here presented.

MAORY (Multi Conjugate Adaptive Optics RelaY) is one of the four instruments for the ELT (Extremely Large Telescope) approved for construction. It is an adaptive optics module able to compensate the wavefront disturbances affecting the scientific observations, achieving high strehl ratio and high sky coverage. MAORY will be installed on the straight-through port of the telescope Nasmyth platform and shall re-image the telescope focal plane to MICADO (the first light imager of the ELT) and in a future second instrument port. A general overview of the present status of the mechanical design of the Main structure is given in this paper.

The Multi Conjugate Adaptive Optics RelaY (MAORY) is the Multi-Conjugated Adaptive Optics (MCAO) module for the European Extremely Large Telescope (ELT). MAORY is one of the ELT first light instruments, designed to feed the Near Infrared Red (NIR) camera MICADO with both MCAO and Single-Conjugated AO (SCAO) operation modes. The optical configuration provides a one to one image of telescope focal surface on the MICADO focal surface (with the additional capability for a second port dedicated to a future instrument), and allows the implementation of two deformable mirrors together with the Laser Guide Star (LGS) and Natural Guide Star (NGS) channels for wavefront sensing and tomographic reconstruction. In this paper we present the status of the optical configuration in the Preliminary Design Review (PDR) framework for the main path optics and the analyses results on the expected optical performance.

The different optical designs that locate the optical elements in the MAORY volume impose a different strategy in the design definition of the optomechanics. Considering the different types of elements in the optical design the optomechanics must satisfy the requirement in terms of stiffness, mass and provide a compensating effect respect to the thermal breathing of the materials. In the paper are presented the solutions taken and the mounts working principle. In particular, the aspects that underline and analysed in the simulation are: 1) The behaviour of the mounts in earthquake condition and in thermal survivor condition that means twenty degrees of variation of temperature. 2) The operational condition, the deformation induced in the optical surface due to the gravity, the alignment, and a variation of temperature. 3) The modal analysis of the structure.

The point spread function reconstruction (PSF-R) capability is a deliverable of the MICADO@ESO-ELT project. The PSF-R team works on the implementation of the instrument software devoted to reconstruct the point spread function (PSF), independently of the science data, using adaptive optics (AO) telemetry data, both for Single Conjugate (SCAO) and Multi-Conjugate Adaptive Optics (MCAO) mode of the MICADO camera and spectrograph. The PSF-R application will provide reconstructed PSFs through an archive querying system to restore the telemetry data synchronous to each science frame that MICADO will generate. Eventually, the PSF-R software will produce the output according to user specifications. The PSF-R service will support the state-of-the-art scientific analysis of the MICADO imaging and spectroscopic data.

The Multi Conjugate Adaptive Optics RelaY (MAORY) for the ESO Extremely Large Telescope (ELT) is an Adaptive Optics module offering Multi-Conjugate (MCAO) and Single-Conjugate (SCAO) compensation modes. In MCAO, it relies on the use of a constellation of Laser Guide Stars (LGS) and up to three Natural Guide Stars (NGS) for atmospheric turbulence sensing, and multiple deformable mirrors for correction, providing uniform, high Strehl and high sky coverage. MAORY will be installed at the Nasmyth focus of the E-ELT and will feed the MICADO first-light diffraction limited imager and a future second instrument. MAORY is being built by a Consortium composed by INAF in Italy, IPAG in France and the School of Physics at the National University of Ireland Galway. In this paper we report about the status of the design of the MAORY Real Time Computer, which is the component in charge of implementing the main AO control loops, as well as of auxiliary computations to keep the loops operating optimally, and of telemetry data collection for postprocessing, monitoring, testing and troubleshooting. We will start by discussing the evolution of requirements towards MAORY RTC, with an emphasis on the main driving ones. Then, we will describe how the analysis of requirements has led to the derivation of the main design parameters. Finally, we will illustrate possible RTC designs satisfying user requirements, while also complying with standards set forth by ESO.

After releasing reference camera solutions in the visible and infrared for natural guide star wavefront sensing with unbeaten performances, we will present the first results of First Light Imaging’s C-BLUE One (formerly introduced under the name “C-MORE”), the first laser guide-star-oriented wavefront sensor camera. Within the Opticon WP2 european funded project which has been set to develop LGS cameras, fast path solutions based on existing sensors had to be explored to provide working-proven cameras to ELT projects ready for the first light schedule. Result of this study, C-BLUE One is a CMOS based camera with 1600x1100 pixels (9um pitch) and up to 660 FPS refresh rate. It has been developed to answer most of the needs of future laser based adaptive optics systems (LGS) to be deployed on 20-40m-class telescopes as well as on smaller ones.

One of the critical components of the AO systems are the WFS detectors that have very challenging requirements of high Quantum Efficiency (QE), and low read noise at high read out speeds. For several years now, ESO has been very active in gathering requirements, planning, and developing detectors and controllers/cameras for the AO systems of the telescope and instruments of the ELT. There cameras are in development: ALICE, LISA and FREDA. For ALICE and LISA, a single camera design approach is being followed with the only difference being the customizable front-ends to support the different type of detector. For the FREDA camera, a different approach is being followed: C-RED One cameras are being procured from First Light Imaging and will be modified by ESO to comply with ELT standards. An update on the progress of this development and measured results of camera test will be provided.

As the new generation of telescopes is coming soon, we need to solve or improve some issues related to the adaptive optics techniques, necessary to fully exploit their extraordinary capabilities in terms of sensitivity and resolution. The Ingot wavefront sensor was thought to overcome some limitations due to the use of artificial sources instead of natural ones: it is designed to cope with the typical elongation of Sodium Laser Guide stars that will be used by the ELTs. Here we present the preliminary tests we performed to properly set up an end-to-end simulator, in order to evaluate the performance of such a device. We describe the different configurations considered and the assumptions we made, discussing also some computational problems we faced building up the tool. We also show the results of the first simulations obtained closing the loop with a mock ELT telescope.

In this report, we present an optical design for a 3-sided reflective pyramid wavefront sensor which allows for the imaging of the pupils onto a single detector. A general approach for this reflective design is demonstrated; however, in effort to implement the optical system into the Shane Telescope’s adaptive optics module, this reflective pyramid wavefront sensor design is constrained by the module’s current specifications. Due to the physical constraints in the AO module, the developed optical design shares an undeviated optical axis with a transmissive wedge solution for discrete modulation. Pupil images were created using a lab test bench that demonstrates the design’s proof of concept. We will discuss the details of the optical design and its motivating parameters using the Shane Telescope’s adaptive optics module.

The MCAO Assisted Visible Imager and Spectrograph (MAVIS) Adaptive Optics Module has very demanding goals to support science in the optical: providing 15% SR in V band on a large FoV of 30arcsec diameter in standard atmospheric conditions at Paranal. It will be able to work in closed loop on up to three natural guide stars down to H=19, providing a sky coverage larger than 50% in the south galactic pole. Such goals and the exploration of a large MCAO system parameters space have required a combination of analytical and endto-end simulations to assess performance, sky coverage and drive the design. In this work we report baseline performance, statistical sky coverage and parameters sensitivity analysis done in the phase-A instrument study.

AOSAT is a python package for the analysis of single-conjugate adaptive optics (SCAO) simulation results. Python is widely used in the astronomical community these days, and AOSAT may be used stand-alone, integrated into a simulation environment, or can easily be extended according to a user’s needs. Standalone operation requires the user to provide the residual wavefront frames provided by the SCAO simulation package used, the aperture mask (pupil) used for the simulation, and a custom setup file describing the simulation/analysis configuration. In its standard form, AOSAT’s "tearsheet" functionality will then run all standard analyzers, providing an informative plot collection on properties such as the point-spread function (PSF) and its quality, residual tip-tilt, the impact of pupil fragmentation, residual optical aberration modes both static and dynamic, the expected high-contrast performance of suitable instrumentation with and without coronagraphs, and the power spectral density of residual wavefront errors. AOSAT fills the gap between the simple numerical outputs provided by most simulation packages, and the full-scale deployment of instrument simulators and data reduction suites operating on SCAO residual wavefronts. It enables instrument designers and end-users to quickly judge the impact of design or configuration decisions on the final performance of down-stream instrumentation.

We describe versatile turbulence simulator for testing and calibration of new techniques for high-resolution imaging of objects outside the Earth’s atmosphere using ground-based instrumentation. Examples here include: dynamic aperture diversity, wave front sensing using multi-aperture phase retrieval, and free-space beam propagation for rapidly re-configurable interferometers. Used in the testing of all of these, the simulator uses a high resolution spatial light modulator in tandem with a lower resolution deformable mirror to simulate atmospheric phase distortions over a wide range of turbulence conditions.

The optimization and scheduling of scientific observations done with instrumentation supported by adaptive optics could greatly benefit from the forecast of PSF figures of merit (FWHM, Strehl Ratio, Encircle Energy and contrast), that depend on the AO instrument, the scientific target and turbulence conditions during the observing night. In this contribution we explore the the possibility to forecast a few among the most useful PSF figures of merit (SR and FWHM). To achieve this goal, we use the optical turbulence forecasted by the mesoscale atmospheric model Astro-Meso-NH on a short timescale as an input for PSF simulation software developed and tailored for specific AO instruments. A preliminary validation will be performed by comparing the results with on-sky measured PSF figures of merit obtained on specific targets using the SCAO systems SOUL (FLAO upgrade) feeding the camera LUCI at LBT and SAXO, the extreme SCAO system feeding the high resolution SPHERE instrument at VLT. This study will pave the way to the implementation of an operational forecasts of such a figure of merits on the base of existing operational forecast system of the atmosphere (turbulence and atmospheric parameters). In this contribution we focus our attention on the forecast of the PSF on-axis.

The vector-Apodizing Phase Plate (vAPP) is a pupil-plane coronagraph that manipulates phase to create darkholes in the stellar PSF. The phase is induced on the circular polarization states through the inherently achromatic geometric phase by spatially varying the fast axis orientation of a half-wave liquid-crystal layer. The two polarized PSFs can be separated, either by a quarter-wave plate (QWP) followed by a polarizing beamsplitter (PBS) for broadband operation, or a polarization sensitive grating (PSG) for narrowband or IFS operation. Here we present new vAPP concepts that lift the restrictions of previous designs and report on their performance. We demonstrated that the QWP+PBS combination puts tight tolerances on the components to prevent leakage of non-coronagraphic light into the dark-hole. We present a new broadband design using an innovative two-stage patterned liquid-crystal element system based on multi-color holography, alleviating the leakage problem and relaxing manufacturing tolerances. Furthermore, we have shown that focal-plane wavefront sensing (FPWFS) can be integrated into the vAPP by an asymmetric pupil. However, such vAPPs suffer from a reduced throughput and have only been demonstrated with a PSG in narrowband operation. We present advanced designs that maintain throughput and enable phase and amplitude wavefront sensing. We also present broadband vAPP FPWFS designs and outline a broadband FPWFS algorithm. Finally, previous dual-beam vAPP designs for sensitive polarimetry with one-sided dark holes were very complex. We show new dual-beam designs that significantly reduce the complexity.

The search for Earth-like exoplanets requires high-contrast and high-angular resolution instruments, which designs can be very complex: they need an adaptive optics system to compensate for the effect of the atmospheric turbulence on image quality and a coronagraph to reduce the starlight and enable the companion imaging. During the instrument design phase and the error budget process, studies of performance as a function of optical errors are needed and require multiple end-to-end numerical simulations of wavefront errors through the optical system. In particular, the detailed analysis of long-exposure images enables to evaluate the image quality (photon noise level, impact of optical aberrations and of adaptive optics residuals, etc.). Nowadays simulating one long but finite exposure image means drawing several thousands of random frozen phase screens, simulating the image associated with each of them after propagation through the imaging instrument, and averaging all the images. Such a process is time consuming, demands a great deal of computer resources, and limits the number of parametric optimization. We propose an alternative and innovative method to directly express the statistics of ground-based images for long but finite exposure times. It is based on an analytical model, which only requires the statistical properties of the atmospheric turbulence. Such a method can be applied to optimize the design of future instruments such as SPHERE+ (VLT) or the planetary camera and spectrograph (PCS - ELT) or any ground-based instrument.

We performed an on-sky MCAO experiment using 4 deformable mirrors (DMs) to analyze the relevance of their sequence to the residual wavefront error. Two DMs were conjugate to 4 and 8 km. The other two DMs were placed in pupil images upstream and downstream of the 4-km and 8-km mirrors. At any time, both high altitude DMs were active but only one pupil DM was active while the other one stayed flat. Firstly, we found that the MCAO control loops using either pupil DM were stable and robust. Dynamic misregistration, which was present for the first pupil DM, was not an immediate problem for the controller. We did not notice an apparent difference when repeatedly switching between the pupil DMs during the operation. A closer analysis of the contrast in the corrected images and AO telemetry indicates an advantage when the pupil correction was applied with the DM that was downstream of the high-altitude DMs. This finding is consistent in several data recorded at different days. The difference, however, is small. A more detailed analysis is probably needed to rule out error sources potentially not considered herein to draw a final conclusion on the optimal sequence of DMs in MCAO and its practical relevance.

Current and future high-contrast imaging instruments require extreme Adaptive Optics (XAO) systems to reach contrasts necessary to directly image exoplanets. Telescope vibrations and the temporal error induced by the latency of the control loop limit the performance of these systems. Optimization of the (predictive) control algorithm is crucial in reducing these effects. We describe how model-free Reinforcement Learning can be used to optimize a Recurrent Neural Network controller for closed-loop adaptive optics control. We verify our proposed approach for tip-tilt control in simulations and a lab setup. The results show that this algorithm can effectively learn to suppress a combination of tip-tilt vibrations. Furthermore, we report decreased residuals for power-law input turbulence compared to an optimal gain integrator. Finally, we demonstrate that the controller can learn to identify the parameters of a varying vibration without requiring online updating of the control law. We conclude that Reinforcement Learning is a promising approach towards data-driven predictive control; future research will apply this approach to the control of high-order deformable mirrors.

The point spread function (PSF) is the impulse response of an optical system. PSFs of an adaptive optics system have very strong variations both in temporal and spatial domain and a stable PSF reconstruction algorithm is required to provide prior information for scientific data processing. In this paper, we report our recent progress in developing a framework for PSF modelling with non-parametric model. The non-parametric PSF model uses compressive wavefront sensing method to build PSFs from wavefront measurements. Then a PSF-NET is used to learn map between PSFs estimated from wavefront sensing and PSFs in different field of views in a ground layer adaptive optics system. We use simulated data to test performance of the non--parametric PSF model and the results show its effectiveness.

In this paper we use artificial neural networks (ANNs) as a nonlinear wavefront predictor for CANARY open-loop telemetry. CANARY is a single channel multi-object adaptive optics demonstrator hosted by the 4.2 m William Herschel Telescope on La Palma island. These datasets were taken by the on-axis 7×7 NGS (natural guide star) Shack-Hartmann wavefront sensor between 28 September and 2 October, 2017. The ANN predictor is trained in simulations, assuming frozen flow turbulence. We show that the ANN predictor did not improve the system performance with a two-frame latency in terms of residual wavefront errors. Analyses with auto-covariance maps show that a stationary layer was observed by CANARY during those nights, indicative of strong dome seeing. This implies the need of a more representative turbulence model for training ANN predictors with non frozen flow observations.

For the new generation of Extremely Large Telescopes the knowledge of atmospheric turbulence conditions is become an information of primary importance to design and optimize all focal instrumentation. In the same way, the forecast of these atmospheric conditions is also of interest to allow both flexible scheduling and long term site testing. Until now we have used weather forecast tools coupled with turbulence models to predict turbulence conditions. In addition, we are developing a predictive statistical learning tool, using a large atmospheric database. Since 2015, the Calern Observatory hosts the Calern Atmospheric Turbulence Station (CATS) which measures during daytime and nighttime, ground meteorological conditions, vertical profiles of the C²_n and all relevant integrated parameters characterizing the optical turbulence. This large CATS database is used as input for our predictive statistical learning tool. This latter should take into account more closely the local specificities, seasonal variations and day/night transitions. The results from these turbulence predictive models and statistical learning tools are presented and discussed.

Wavefront sensing (WFS) in the context of Adaptive Optics requires intensive computational processing for the reconstruction of the wavefront. In this work, an artificial Neural Network will be trained based using real Pyramid WFS data in order to estimate the Karhunen-Lo´eve modes of the Large Binocular Telescope Adaptive Optics system.

We have recently proposed the deep learning wavefront sensor, capable of directly estimating Zernike coefficients of aberrated wavefronts from a single intensity image by using a convolutional neural network. However, deep neural networks demand an intensive training stage, where more training examples allow to improve the accuracy and increase the amount of the estimated Zernike modes. Since low order aberrations such as tip and tilt only produce space-invariant motion of the PSF, we propose to treat tip and tilt estimation separately when training the deep learning wavefront sensor, decreasing the training efforts while keeping the wavefront sensor performance. In this paper, we also introduce and test simpler architectures for deep learning wavefront sensing, while exploring the impact of reducing the number of pixels to estimate a given amount of Zernike coefficients. Our preliminary results indicate that we can achieve a significant prediction speedup aiming for real time adaptive optics systems.

We present a two-staged approach to wide-field wavefront sensing and demonstrate its ability to estimate and enhance image quality for the upcoming Rubin Observatory. The first stage makes local wavefront estimates with a convolutional neural network; the second stage uses linear regression to solve for the global optical state. The Rubin Observatory will have a 3.5 degree field of view, highly degenerate optical system, and curvature wavefront sensing system, making it the perfect test case. We trained our model on 600,000 simulated Rubin Observatory intra and extra-focal star images (donuts). It learns to estimate the optics contribution to the wavefront and separate it from a myriad of other contributions. This computationally efficient approach can process 1,000 times the number of donuts as proposed alternatives. This significant increase in bandwidth leads to a richer and more accurate characterization of the evolution of the telescope optics.

A classical closed-loop adaptive optics system with a Shack-Hartmann wavefront sensor (WFS) relies on a center of gravity approach to process the WFS information and an integrator with gain to produce the commands to a Deformable Mirror (DM) to compensate wavefront perturbations. In this kind of systems, noise in the WFS images can propagate to errors in centroids computation, and thus, lead the AO system to perform poorly in closed-loop operations. In this work, we present a deep supervised learning method to denoise the WFS images based on convolutional denoising autoencoders. Our method is able to denoise the images up to a high noise level and improve the integrator performance almost to the level of a noise-free situation.

We describe the operation of the infrared wavefront sensing based Adaptive Optics system CIAO. The Coudé Infrared Adaptive Optics (CIAO) system is a central auxiliary component of the Very Large Telescope interferometer (VLTI). It enables in particular Galactic Center observations using the GRAVITY interferometric instrument. CIAO compensates for phase disturbances caused by atmospheric turbulence, which all four 8 m Unit Telescopes (UT) experience during observation. Each of the four CIAO units generates an almost diffraction-limited image quality at its UT, which ensures that maximum flux of the observed stellar object enters the input fibers of GRAVITY. We present CIAO performance data obtained in the first 3 years of operation. We describe how CIAO is configured and used for observations with GRAVITY. We focus on the outstanding features of the infrared sensitive Saphira detector, which is used for the first time on Paranal, and show how it works as a wavefront sensor detector.

MagAO-X is a new “extreme” adaptive optics system for the Magellan Clay 6.5 m telescope which began commissioning in December, 2019. MagAO-X is based around a 2040 actuator deformable mirror, controlled by a pyramid wavefront sensor operating at up to 3.6 kHz. When fully optimized, MagAO-X will deliver high Strehls (< 70%), high resolution (19 mas), and high contrast (< 1 × 10⁻⁴) at Hα (656 nm). We present a brief review of the instrument design and operations, and then report on the results of the first-light run.

The Multi-Core Integral-Field Unit (MCIFU) is a new diffraction-limited near-infrared integral-field unit for exoplanet atmosphere characterization with extreme adaptive optics (xAO) instruments. It has been developed as an experimental pathfinder for spectroscopic upgrades for SPHERE+/VLT and other xAO systems. The wavelength range covers 1.0 um to 1.6um at a resolving power around 5000 for 73 points on-sky. The MCIFU uses novel astrophotonic components to make this very compact and robust spectrograph. We performed the first successful on-sky test with CANARY at the 4.2 meter William Herschel Telescope in July 2019, where observed standard stars and several stellar binaries. An improved version of the MCIFU will be used with MagAO-X, the new extreme adaptive optics system at the 6.5 meter Magellan Clay telescope in Chile. We will show and discuss the first-light performance and operations of the MCIFU at CANARY and discuss the integration of the MCIFU with MagAO-X.

We present the design of the Adaptive Optics System for the new Turkish 4-m telescope (DAG). The AO will use a pyramid WFS, with a double prism and a no noise EM-CCD camera to allow for oversampling of the pupil images and a relaxation of the prism manufacturing tolerances. In order to use the high modal resolution of the P-WFS allowed by the adjustment of the modulation angle, we implement a high order deformable mirror with 468 actuators, which will permit to use the system in extreme AO correction mode. The P-WFS optical design has been largely inspired by NFIRAOS truth WFS. The number of optical surfaces has been reduced to the bare minimum. An atmospheric dispersion compensator is introduced around the tip-tilt modulation mirror. In this proceeding, we present the detail of the optical design steps for all the components of the system.

We present in this report the design of the atmospheric dispersion compensator for the adaptive optics system of DAG, the new 4 m Turkish telescope. An Amici configuration has been chosen, made of a pair of doublets prisms, located on both side of the tip-tilt mirror of the system’s pyramid wavefront sensor. Our design methodology, using a Python controlled ZEMAX model, is described, with our results, as well as the design of a triplet lens to compensate for the remaining pupil nutation.

ERIS (Enhanced Resolution Imager and Spectrograph) is the new AO instrument for the ESO Very Large Telescope. It includes the 1-5 micron camera NIX, the 1-2.5 micron spectrograph SPIFFIER (a refurbished version of SPIFFI), an Adaptive Optics module able to provide single-conjugate adaptive correction using both NGS and LGS stars and an internal Calibration Unit. The ERIS construction is under completion and commissioning at VLT UT4 will start on the 2nd half of 2020. The as-built capabilities and performances of the Calibration Unit are presented in this paper.

In practice, technologies attempting to recover direct images of extra-solar planets run into noise floors governed by systematics (most notably, quasi-static speckles) before reaching fundamental limits (such as photon noise). To enhance detection reach to higher contrasts, discrimination by exploiting distinctive planetary signatures have been proposed. Here we explore a novel possibility: detecting exoplanets around bright variable stars based on the variability-phase difference between the speckles and the reflected light from the planet. Hot variable stars (the kind most favorable to this idea) host relatively distant Habitable Zones, which will allow a considerable phase delay to be displayed by planet in reflection. We have carried out a systematic series of simulations and analysis to explore the potential for this method. We show that this technique could improve contrast reach of an extreme-AO imagery by a factor of 5-10 against speckle noise.

We recently proposed a new lucky imaging technique, the Power Spectrum Extended (PSE), adapted for image reconstruction of short-exposure astronomical images in case of weak turbulence or partial adaptive optics correction. In this communication we show applications of this technique to observations of about 30 binary stars in H band with the 1m telescope of the Calern C2PU observatory. We show some images reconstructed at the diffraction limit of the telescope and provide measurements of relative astrometry and photometry of observed couples.

We propose, in the framework of high angular resolution imaging, a new image reconstruction technique denoted as Power Spectrum Extended (PSE). This method allows to perform the reconstruction of point-like and extended objects from a series of short-exposure frames, and is well adapted to post-adaptive optics images and/or small diameter telescopes. The algorithm works in the Fourier domain. It combines information from the average power spectrum of images with phase information estimated from an ad hoc shift-and-add process. It can be used together with a Lucky Imaging selection algorithm. It gives very encouraging results, even on very extended objects (larger than the isoplanatic angle) and at low light level (photon counting). In this communication, we present results obtained on astronomical objects as well as artificial satellites. We also show a comparison of performance with a reference Lucky Imaging technique.

Next generation AO systems at Gemini Observatory will record full rate telemetry during all closed loop observations. This telemetry data will be made available to the science data end user alongside their science data in order to facilitate techniques such as PSF reconstruction and atmospheric turbulence profiling and over time will build up a significant public AO telemetry archive. We explore some of the practical implications on this and seek to explore community standards such as common data formats and software interoperability with other groups planning on similar systems.

High-resolution imaging with large ground-based telescope is challenging due to atmospheric turbulence. Adaptive optics (AO) system can provide real-time compensation for the wavefront distortion in the pupil of the telescope. However, the observed images still suffer from a blurring caused by the residual wavefront. Numerical post-processing with a good approximation of the residual wavefront can help to effectively remove the blur. In this paper, a gradients measurement model for the Shack-Hartmann wavefront sensor (WFS) in a closed-loop AO system is built. The model is based on the frozen flow hypothesis with knowledge of the wind velocities of atmospheric turbulence layers. Then a high resolution residual wavefront reconstruction method using multiframe Shack-Hartmann WFS measurements and deformable mirror voltages is presented. Numerical results show that the method can effectively improve the spatial resolution and accuracy of the reconstructed residual wavefront.

The planet detection thresholds of space-based coronagraphs are predicted to lie within an order of magnitude from their theoretical (shot-noise) limits. Ground-based telescopes, on the other hand, are limited by larger systematic uncertainties in the point spread function (PSF) of the residual light which rapidly fluctuates due to atmospheric turbulence. The PSF is affected by Adaptive Optics (AO) which reduce the intensity of the speckles but also make them less predictable. Although not a common practice, it is possible to take millisecond exposures of the so-called “frozen” speckles and record the history of AO controls, in which case the collected data resembles that of simulated space coronagraphs. In this work we use the HEEPS simulation of the EELT/METIS to assess the applicability of this newly-developed space-oriented approach to ground-based postprocessing. Unlike intensity-based algorithms, this method formulates the estimation problem in terms of the electric field of the speckles and therefore can incorporate controls history and various temporal models of the electric field variations. In our simulations, we artificially introduced small deformable mirror (DM) probes on top of AO controls, and achieved a post-processing error lower by a factor of 2 than that of Angular Differential Imaging (ADI). However, our attempt at incorporating the AO history without DM probes, has so far resulted in higher errors than ADI.

GIRMOS is a multi-object adaptive optics spectrograph in the near-infrared currently being designed for the Gemini North telescope. It will allow to observe with high-quality adaptive optics correction multiple targets selected from a large field. To increase the efficiency of the nightly observations, it is important to provide a feedback in real time to operators and observers on the quality of the point-spread function, using intuitive metrics such as the full width at half maximum, the Strehl ratio and the encircled energy. We present a set of simple analytical expressions derived from other works that use the measurement of the wavefront residuals. We then compare the results to an end-to-end AO simulation of GIRMOS. We show that this approach works well with the estimation of the full width at half maximum and the Strehl ratio, while it is less successful with the encircled energy.

In 2013, Frazin introduced a statistical inference algorithm that uses simultaneous millisecond exposures in the science camera (SC) and wavefront sensor (WFS) to jointly estimate this NCPA, as well as the exoplanetary image. Here, we provide an update on the advancement of the method, with a focus on the ability to compensate NCPA in real time, and an evaluation of the effect of readout noise on the contrast. Finally, we make conclusions about the practicality of implementing the algorithm on modern and future telescopes, discussing factors such as real time computational requirements and high fidelity model calibrations.

We present an analysis of the long-term performance of the W. M. Keck Observatory Laser Guide Star Adaptive Optics (LGS-AO) system and explore factors that influence the overall AO performance most strongly. Astronomical surveys can take years or decades to finish, so it is worthwhile to characterize the AO performance on such timescales in order to better understand future results. Keck Observatory has two of the longest-running LGS-AO systems in use today and represents an excellent test-bed for investigating large amounts of AO data. Here, we use LGS-AO observations of the Galactic Center (GC) from 2005 to 2019, all taken with the NIRC2 instrument on the Keck-II telescope, for our analysis. We combine image metrics with AO telemetry files, MASS/DIMM turbulence profiles, seeing information, and weather data in one cohesive dataset to highlight areas of potential performance improvement and train a simple machine learning algorithm to predict the delivered image quality given current atmospheric conditions. The complete dataset will be released to the public as a resource for testing new predictive control and PSF-reconstruction algorithms.

The Exoplanet Imaging Data Challenge is a community-wide effort meant to offer a platform for a fair and common comparison of image processing methods designed for exoplanet direct detection. For this purpose, it gathers on a dedicated repository (Zenodo), data from several high-contrast ground-based instruments worldwide in which we injected synthetic planetary signals. The data challenge is hosted on the CodaLab competition platform, where participants can upload their results. The specifications of the data challenge are published on our website https://exoplanet-imaging-challenge.github.io/. The first phase, launched on the 1st of September 2019 and closed on the 1st of October 2020, consisted in detecting point sources in two types of common data-set in the field of high-contrast imaging: data taken in pupil-tracking mode at one wavelength (subchallenge 1, also referred to as ADI) and multispectral data taken in pupil-tracking mode (subchallenge 2, also referred to as ADI+mSDI). In this paper, we describe the approach, organisational lessons-learnt and current limitations of the data challenge, as well as preliminary results of the participants’ submissions for this first phase. In the future, we plan to provide permanent access to the standard library of data sets and metrics, in order to guide the validation and support the publications of innovative image processing algorithms dedicated to high-contrast imaging of planetary systems.

A multi-cascade adaptive optical system for imaging and image stabilization for the Large Solar Vacuum Telescope is described. This system was created in 2017 by specialists of the V.E. Zuev Institute of Atmospheric Optics SB RAS, Tomsk, with the technical support of the Institute of Solar-Terrestrial Physics SB RAS, Irkutsk. The system has been tested at the Large Solar Vacuum Telescope (Baikal Astrophysical Observatory) and demonstrated its efficiency. Along with the first cascade of adaptive image stabilization by a tip-tilt corrected mirror, this system employs the second imaging cascade based on correction with a flexible mirror controlled by a specialized wavefront sensor, as well as the third cascade for real-time post-detector processing of video camera frames. Reliable experimental data confirming the efficiency of the multi-cascade adaptive system for image formation and stabilization have been obtained. Three highrate digital video cameras recording simultaneously digital images with rates from 300 to 980 frames per second were used to test the system. The mirror correcting wavefront tilts and operating in a closed optical feedback loop was controlled by the specially developed software including the fast correlation tracking algorithm. The post-detector digital imaging was performed with a special software for processing of video camera frames in real time with the use of modern high-speed parallel algorithms based on the Intel MKL and IPP libraries.

On-sky testing of new instrumentation concepts is required before they can be incorporated within facility-class instrumentation with certainty that they will work as expected within a real telescope environment. Increasingly, many of these concepts are not designed to work in seeing-limited conditions and require an upstream adaptive optics system for testing. Access to on-sky AO systems to test such systems is currently limited to a few research groups and observatories worldwide, leaving many concepts unable to be tested. A pilot program funded through the H2020 OPTICON program offering up to 15 nights of on-sky time at the CANARY Adaptive Optics demonstrator is currently running but this ends in 2021. Pre-run and on-sky support is provided to visitor experiments by the CANARY team. We have supported 6 experiments over this period, and plan one more run in early 2021. We have recently been awarded for funding through the H2020 OPTICON-RADIO PILOT call to continue and extend this program up until 2024, offering access to CANARY at the 4.2m William Herschel Telescope and 3 additional instruments and telescopes suitable for instrumentation development. Time on these facilities will be open to researchers from across the European research community and time will be awarded by answering a call for proposals that will be assessed by an independent panel of instrumentation experts. Unlike standard observing proposals we plan to award time up to 2 years in advance to allow time for the visitor instrument to be delivered. We hope to announce the first call in mid-2021. Here we describe the facilities offered, the support available for on-sky testing and detail the eligibility and application process.

The Adaptive Optics (AO) system at the Large Binocular Telescope (LBT) in conjunction with the f/30 camera on the LBT Utility Camera in the Infrared instruments (LUCI) can achieve diffraction limited image quality over a 30" × 30" field of view (FOV). The AO system also includes the ability to deliver only 11 modes of correction (including tip and tilt) to remove residual aberrations and jitter. When combined with the f/3.75 camera on either LUCI, this Enhanced Seeing Mode (ESM) can achieve an uniform angular resolution of 0".22 over a 4' × 4' FOV in the best natural seeing conditions. Further, unlike full AO, ESM can be used for binocular longslit and multi-object high-resolution spectroscopy (R~10,000). It has been further demonstrated that even in poor seeing conditions (θ << 1′′.5) the image quality delivered to the LUCI focal stations is improved by 2-3× from 1-2.5 microns. It is proposed that ESM should become a standard observational mode for near-Infrared LBT observations.

MAPS, MMT Adaptive optics exoPlanet characterization System, is the upgrade of the adaptive optics system for 6.5-m MMT. It is an NSF MSIP-funded project that includes developing an adaptive-secondary mirror, visible and near-infrared pyramid wavefront sensors, and the upgrade of Arizona infrared imager and echelle spectrograph (ARIES) and MMT High Precision Imaging Polarimeter (MMTPol) science cameras. This paper will present the design and development of the visible pyramid wavefront sensor, VPWFS. It consists of an acquisition camera, a fast-steering tip-tilt modulation mirror, a pyramid, a pupil imaging triplet lens, and a low noise and high-speed frame rate based CCID75 camera. We will report on hardware and software, present the laboratory characterization results of individual subsystems, and outline the on-sky commissioning plan.

We present the final design of the Giant Magellan Telescope (GMT) Adaptive Secondary Mirrors System (ASMS), which comprises seven 1m class deformable mirrors segments plus seven hexapod positioners. Each deformable mirror is based on the well established contactless technology developed by AdOptica and already successfully deployed in several 8m class telescopes. The challenge for GMT is that the seven deformable mirrors will function as a single mirror. A subscale prototype made of 72 actuators has been produced to secure system final design: test setup and preliminary results are presented.

The MMT Adaptive optics exoPlanet characterization System (MAPS) is a broad overhaul and upgrade of AO instrumentation at the 6.5-m MMT observatory, from deformable secondary mirror, through pyramid wavefront sensors in both the visible and near-infrared, to improved science cameras. MAPS is an NSF MSIP-funded program whose ultimate goal is a facility optimized for exoplanet characterization. Here we describe the laboratory testing and calibration of one MAPS component: the refurbished MMT adaptive secondary mirror (ASM). The new ASM includes a complete redesign of electronics and actuators, including simplified hub-level electronics and digital electronics incorporated into the actuators themselves. The redesign reduces total power to ⪅300W, from the original system’s 1800W, which in turn allows us to eliminate liquid cooling at the hub with no loss of performance. We present testing strategies, results, and lessons learned from laboratory experience with the MAPS ASM. We discuss calibrations first on the level of individual actuators, including capacitive position sensing, force response function, and individual closed-loop position control with an improved control law. We then describe investigations into the full ASM system – hub, actuators, thin shell, and human – to understand how to optimize interactions between components for dynamical shape control using a feedforward matrix. Finally, we present our results in the form of feedforward matrix and control law parameters that successfully produce a desired mirror surface within 1ms settling time.

Adaptive optics is an essential technology for large ground-based telescopes to correct atmospheric disturbances. Presently the large-aperture adaptive deformable mirror uses piezoelectric actuator or voice coil actuator, however both of them have their own problems. Then Giant Magnetostrictive Material (GMM) actuator has great advantage as the actuator for large aperture adaptive mirror, which has large stroke, high bandwidth, high precision and doesn’t require high drive voltage. The research ‘s aim is to use the GMM actuator to drive the deformable mirror, and to build a large-aperture adaptive mirror calibration experiment platform to study this new material actuator in the adaptive mirror, at the same time adaptive deformable mirror’s control method would be studied. This research could be considered as a pre-research for GLAO system of Chinese large optical infrared telescope.

The adaptive secondary mirrors (ASMs), being an integral part of the telescope optical train, have huge advantages over other wave-front correctors. At the same time, because of this specific characteristic, high performance and high reliability is required from an ASM. In this paper, we report on algorithm/software developments at the Large Binocular Telescope designed to improve performance and reliability of the two 672-voice-coil-actuators ASMs. By making use of the ASMs telemetry, we are able to intervene when critical condition occurs, monitor the daily operation of the ASMs and review the long-term trends to plan future maintenance activities.

In this paper, we propose a novel control method for high precision position control of large deformable mirrors with voice coil actuators. The controller consist of a low frequency force feedforward and a high frequency local position feedback.using force feedforward control, the dynamics of mirror can be contolled in faster settling times, and the local position controller based on the active disturbance rejection control(ADRC) algorithm guarantee the final stability of the high precision shape. we present the progress of the unit construction with a 7-actuator sub-system used to test the control method. Finally, by using experimental test, results confirm the validity of the proposed control scheme.

TNO and industrial partners are developing a new type of adaptive secondary mirrors (ASM) for the University of Hawaii 2.2-meter telescope, consisting of 210 actuators, in an overall volume of ø63cm by 15cm height, and having an aspherical convex mirror-shell of 3,5mm thickness. The novel actuator technology enables a compact system without active cooling that can be retro-fitted within the same mass and volume of an existing passive secondary mirror. This development enables affordable and reliable ASM systems for the world’s larger telescopes as well as the many telescopes in the 2-4 meter class. This paper presents the overall design of this ASM and focusses on the performance analysis regarding its figure quality, its dynamical behavior and the related closed loop performances.

Deformable mirrors are becoming more and more important elements in the astronomical field, both for development of active and adaptive optics. PCDMs behave in a completely different way respect to the traditional ones, since a pattern of light creates virtual actuators, whose size and density can be freely modulated. PCDMs consist in a slab of photoconductive material with a reflective membrane placed at a certain distance from the photoconductor, creating a capacitor. In this paper will be presented the mechanical solution adopted in order to realize a prototype and the setup used in order to start the characterization of the different component. A critical analysis will be performed on the sensitivity of the system to the different dimension that characterize the system itself, like the distance between the membrane and the photoconductor and the membrane tension. The result presented will be relate to the static deformation of the membrane using the DC current.

With the exception of the two prime focus cameras, all the instruments on the Large Binocular Telescope (LBT) use the two advanced 672-voice-coil-actuators adaptive secondary mirrors (ASMs). Based on 10 years of ASMs operation experience, and taking advantage of new technology developments, we decided to upgrade some of the ASMs hardware, to increase their performance and reliability. In this paper, we describe these improvements, i.e., upgrade of the power backplanes used in the ASM electronic control system, integration of an accelerometer-based tip-tilt vibration suppression system and upgrade of the optical calibration interferometers.

An Adaptive secondary mirror (ASM) allows for the integration of adaptive optics (AO) into the telescope itself. Adaptive secondary mirrors, based on hybrid variable reluctance (HVR) actuator technology, developed by TNO, provide a promising path to telescope-integrated AO. HVR actuators have the advantage of allowing mirrors that are sti↵er, more power ecient, and potentially less complex than similar, voice-coil based ASM’s. We are exploring the application of this technology via a laboratory testbed that will validate the technical approach. In parallel, we are developing conceptual designs for ASMs at several telescopes including the Automated Planet Finder Telescope (APF) and for Keck Observatory. An ASM for APF has the potential to double the light through the slit for radial velocity measurements, and dramatically improved the image stability. An ASM for WMKO enables ground layer AO correction and lower background infrared AO observations, and provides for more flexible deployment of instruments via the ability to adjust the location of the Cassegrain focus.

Advancements in making high-efficiency actuators are an enabling technology for building the next generation of large-format deformable mirrors. The Netherlands Organization for Applied Scientific Research (TNO) has developed a new style of variable-reluctance actuator that requires approximately eighty times less power to operate as compared to the traditional style of voice-coil actuators. We present the performance results from laboratory testing of TNO's 57-actuator large-format deformable mirror from measuring the influence functions, linearity, hysteresis, natural shape flattening, actuator cross-coupling, creep, repeatability, and actuator lifetime. We measure a linearity of 99.4 ± 0.33% and hysteresis of 2.10 ± 0.23% over a stroke of 10 microns, indicating that this technology has strong potential for use in on-sky adaptive secondary mirrors (ASMs). We summarize plans for future lab prototypes and ASMs that will further demonstrate this technology.

Wavefront sensor (WFS) design typically focuses on reference sources at the two extremes of spatial coherence: –spatially coherent natural guide stars (NGS) and spatially incoherent laser guide stars (LGS). We propose a hybrid WFS architecture for sources that fall between those two extremes such as might be achieved with an uplink corrected LGS source. This architecture uses a lenslet array to segment the pupil plane, but the subaperture size is based on the coherence area of the reference source, and a separate WFS technique behind each lenslet is used to achieve the desired spatial sampling of the wavefront. The initial concept presented here is a hybrid Shack-Hartmann Pyramid WFS, though the concept can be applied to other WFS techniques.

The Sodium Laser Guide Star (Na-LGS) on the sky is not point-like, rather cigar-like when launched from the side of a large (or extremely large) telescope. The Na-LGS’s 3D nature gave birth to the idea of a new pupil-plane wavefront sensor that can be deployed in a similar 3D manner - the Ingot Wavefront Sensor (I-WFS). The design of the I-WFS has developed over the last two years, and currently, the ingot prism has 3-faces, creating three pupils. Wavefront sensing can be done using these three pupils themselves as the signals or the slopes generated by the pupils. At the INAF-Padova laboratory, we have realized a test-bench simulating the ELT∗ characteristics to test the I-WFS characteristics and an alignment procedure. We use simulations and lab data to compare, learn, and define a robust alignment procedure. Eventually, we expect to have an entirely automatized alignment procedure using the optical feedback from the I-WFS. In this article, we report the comparison between the laboratory data and the simulations representing (1) the sensitivity measurements of ingot prism misalignment for each degree of freedom with respect to its ideal, aligned position, and (2) the response of the I-WFS to known aberrations using a deformable lens. The final goal is the definition and description of the procedure to align the I-WFS.

This paper investigates the performance and optimization of the Geometric Wavefront Sensor (GWFS) in openloop wavefront sensing, along with the Curvature Wavefront Sensor (CWFS) and Shack-Hartmann Wavefront Sensor (SH-WFS). The GWFS uses a ray tracing process to calculate the displacement of intensity fluctuations from two defocused point source images. Various parameters within the GWFS – such as the signal-to-noise ratio (SNR) sensitivity, the number of Radon angles, the virtual propagation distance, and the number of reconstruction modes – are explored on a laboratory test bench. We found that the GWFS wavefront estimate error experiences an inverse relationship to the SNR, a minimum of 5 Radon angles is required to accurately estimate the single Zernike mode wavefronts (Z₄ – Z₁₅), the virtual propagation distance is confined by ray crossing and Fresnel diffraction effects, and the number of reconstruction Zernike modes is limited by noise amplification and over-fitting. This paper demonstrates the capabilities of the GWFS, illustrates the resulting wavefront estimates, and confirms the superior performance of the GWFS compared to the CWFS. The optimized GWFS will be utilized at Mt. John University Observatory (MJUO) in New Zealand for satellite and space debris imaging and tracking

Reliable wavefront prediction can improve adaptive optics (AO) performance, along with a proper control implementation. The accuracy of the estimated wind vector of the conjugated layers from AO telemetry is a crucial factor in the stability of the AO loop. For a layer-oriented MCAO system, the wind vector of the conjugated layer can be directly extracted from the corresponding wavefront sensor data. We investigate wind vector extraction using laboratory wavefront sensor data from LINC-NIRVANA (LN). The LN MCAO system senses and corrects for two atmospheric turbulent layers, the ground layer and a highaltitude layer (≈ 7km above the telescope pupil). For the ground layer, the stars’ footprints overlap completely. However, for the high layer, the footprints are spatially separated according to the asterism, and we must deal with a partially illuminated scenario. Reliable wavefront prediction, given the wind vector from AO telemetry, can virtually fill the non-illuminated sub-apertures in the direction of the wind, improving the performance of the high layer closed-loop. In this paper, we look into the efficacy of the wind velocity extraction using LN as the lab-setup for both fully and partially illuminated scenarios.

We present the results of the evaluation of the ensquared energy of eight commercially available and custom made Microlens arrays (MLAs) with different focal length Plano-Convex microlens. The highest efficiency is observed with a 300 μm pitch MLA with no AR-coating and square apertures, which show 79% light ensquared within the first dark ring compared to the uniform illumination of the sub-aperture. To quantitatively explain the observed difference in the ensquared energy, we measured the surface shape of these MLAs using a laser interferometer. The comparison between the ensquared energy and the surface shape inferred that the lower ensquared energy of a MLA than the other MLAs with same 300 μm pitch can be explained with the deviation of the ideal shape at the outer part of the each lens.

Residual phasing errors from segmented mirror telescopes can significantly inhibit the performance of an adaptive optics (AO) system. One approach to quantify these errors utilizes the imaging capabilities of a telescope’s instrument suite; quantification requires images that have observed the primary, therefore these images should be on-sky and AO-corrected in the absence of a source that views the primary. An image-based phase estimation technique that can potentially make this quantification is Phase Diversity, whereby focussed/defocussed images of a bright star are compared with models to estimate phase. Traditional use of this technique with on-sky images can be difficult due to atmospheric evolution between image pairs. This is further compounded due to both NCPA and the partial AO correction of phasing errors persisting in on-sky images. Here we propose a technique that can mitigate the atmospheric effects, estimate the NCPA and assess phasing errors under partial AO correction.

The Sodium Laser Guide Star (LGS) is an elongated object in a 3D volume. This produces a significant elongation on many of the Shack-Hartmann wavefront sensor spots that the ELT instruments use for wavefront sensing. The Ingot Wavefront Sensor (I-WFS) has been proposed as a possible solution to deal with the 3D nature of the LGS. We developed an end-to-end numerical tool of the I-WFS to perform system analysis of a closed-loop complete system. We considered the generation of the input turbulence, deformable mirror definition and control, and, of course details, of the I-WFS. It needs a 3-Dimensional description to fully take into account the elongation effect across the vertical (propagation) axis. The I-WFS has been simulated similarly to the Pyramid Wavefront Sensor, as a combination of Foucault knife-edge sensors. In parallel to numerical simulations development, we had the opportunity to perform laboratory testing of the I-WFS at the LOOPS Adaptive Optics test bench (at LAM), using a Spatial Light Modulator. This device is able to produce a high definition phase mask that can mimic two-dimensional I-WFS behaviour. In this framework, we report a preliminary discussion both for the simulations and the closed-loop data analysis.

LINC-NIRVANA at the LBT has a dual MCAO system using solely natural guide stars. A multi pyramid WFS provides the slopes to close two independent loops for ground and high layer correction, as foreseen by the Layer Oriented scheme. The projection of the deformable mirrors actuators pattern on the WFS cameras rotates, since mechanical (ground) and optical (high) derotation provides the field rotation correction needed to keep the WFS on the reference stars. We reported in the previous conferences that we succeed in obtaining valid control matrices through numerical interpolation of a few calibrated interaction matrices registered for different clocking angle. We successfully tested a different approach based on a synthetic WFS and DM model. We proved that control matrices computed by the inversion of the interaction matrices generated from the model were effectively working on the real system closing high-order correction loop on the sky, providing better performance.

Focal plane wavefront sensing is an elegant solution for wavefront sensing since near-focal images of any source taken by a detector show distortions in the presence of aberrations. Non-Common Path Aberrations and the Low Wind Effect both have the ability to limit the achievable contrast of the finest coronagraphs coupled with the best extreme adaptive optics systems. To correct for these aberrations, the Subaru Coronagraphic Extreme Adaptive Optics instrument hosts many focal plane wavefront sensors using detectors as close to the science detector as possible. We present seven of them and compare their implementation and efficiency on SCExAO. This work will be critical for wavefront sensing on next generation of extremely large telescopes that might present similar limitations.