”MagAO" is the adaptive optics instrument at the Magellan Clay telescope at Las Campanas Observatory, Chile. MagAO has a 585-actuator adaptive secondary mirror and 1000-Hz pyramid wavefront sensor, operating on natural guide stars from R-magnitudes of -1 to 15. MagAO has been in on-sky operation for 166 nights since installation in 2012. MagAO's unique capabilities are simultaneous imaging in the visible and infrared with VisAO and Clio, excellent performance at an excellent site, and a lean operations model. Science results from MagAO include the first ground-based CCD image of an exoplanet, demonstration of the first accreting protoplanets, discovery of a new wide-orbit exoplanet, and the first empirical bolometric luminosity of an exoplanet. We describe the status, report the AO performance, and summarize the science results. New developments reported here include color corrections on red guide stars for the wavefront sensor; a new field stop stage to facilitate VisAO imaging of extended sources; and eyepiece observing at the visible-light diffraction limit of a 6.5-m telescope. We also discuss a recent hose failure that led to a glycol coolant leak, and the recovery of the adaptive secondary mirror (ASM) after this recent (Feb. 2016) incident.

We present the integration status for 'imaka, the ground-layer adaptive optics (GLAO) system on the University of Hawaii 2.2-meter telescope on Maunakea, Hawaii. This wide-field GLAO pathfinder system exploits Maunakea's highly confined ground layer and weak free-atmosphere to push the corrected field of view to ∼1/3 of a degree, an areal field approaching an order of magnitude larger than any existing or planned GLAO system, with a FWHM ∼ 0.33" in the visible and near infrared. We discuss the unique design aspects of the instrument, the driving science cases and how they impact the system, and how we will demonstrate these cases on the sky.

Vertical profiles of the atmospheric optical turbulence strength and velocity is of critical importance for simulating, designing, and operating the next generation of instruments for the European Extremely Large Telescope. Many of these instruments are already well into the design phase meaning these profies are required immediately to ensure they are optimised for the unique conditions likely to be observed. Stereo-SCIDAR is a generalised SCIDAR instrument which is used to characterise the profile of the atmospheric optical turbulence strength and wind velocity using triangulation between two optical binary stars. Stereo-SCIDAR has demonstrated the capability to resolve turbulent layers with the required vertical resolution to support wide-field ELT instrument designs. These high resolution atmospheric parameters are critical for design studies and statistical evaluation of on-sky performance under real conditions. Here we report on the new Stereo-SCIDAR instrument installed on one of the Auxillary Telescope ports of the Very Large Telescope array at Cerro Paranal. Paranal is located approximately 20 km from Cerro Armazones, the site of the E-ELT. Although the surface layer of the turbulence will be different for the two sites due to local geography, the high-altitude resolution profiles of the free atmosphere from this instrument will be the most accurate available for the E-ELT site. In addition, these unbiased and independent profiles are also used to further characterise the site of the VLT. This enables instrument performance calibration, optimisation and data analysis of, for example, the ESO Adaptive Optics facility and the Next Generation Transit Survey. It will also be used to validate atmospheric models for turbulence forecasting. We show early results from the commissioning and address future implications of the results.

The Thirty Meter Telescope (TMT) first light instrument IRIS (Infrared Imaging Spectrograph) will complete its preliminary design phase in 2016. The IRIS instrument design includes a near-infrared (0.85 - 2.4 micron) integral field spectrograph (IFS) and imager that are able to conduct simultaneous diffraction-limited observations behind the advanced adaptive optics system NFIRAOS. The IRIS science cases have continued to be developed and new science studies have been investigated to aid in technical performance and design requirements. In this development phase, the IRIS science team has paid particular attention to the selection of filters, gratings, sensitivities of the entire system, and science cases that will benefit from the parallel mode of the IFS and imaging camera. We present new science cases for IRIS using the latest end-to-end data simulator on the following topics: Solar System bodies, the Galactic center, active galactic nuclei (AGN), and distant gravitationally-lensed galaxies. We then briefly discuss the necessity of an advanced data management system and data reduction pipeline.

We overview the current status of photometric analyses of images collected with Multi Conjugate Adaptive Optics (MCAO) at 8–10m class telescopes that operated, or are operating, on sky. Particular attention will be payed to resolved stellar population studies. Stars in crowded stellar systems, such as globular clusters or in nearby galaxies, are ideal test-particles to test AO performance. We will focus the discussion on photometric precision and accuracy reached nowadays. We briefly describe our project on stellar photometry and astrometry of Galactic globular clusters using images taken with GeMS at the Gemini South telescope. We also present the photometry performed with DAOPHOT suite of programs into the crowded regions of these globulars reaching very faint limiting magnitudes K_s ∼21.5 mag on moderately large fields of view (∼1.5 arcmin squared). We highlight the need for new algorithms to improve the modeling of the complex variation of the Point Spread Function (PSF) across the field of view. Finally, we outline the role that large samples of stellar standards plays in providing a detailed description of the MCAO performance and in precise and accurate colour-magnitude diagrams.

GeMS is the multi-conjugate adaptive optics instrument at the Gemini South telescope in Chile, the first facility-class MCAO system and the first to use laser guide stars. During its science verification period we have observed the Galactic globular cluster NGC 1851 and here we discuss the optimization of the analysis techniques that we adopt to extract science-ready photometric measurements. We use the large number of stars in the field of view to determine with high accuracy the PSF model for the profile fitting photometry. Understanding the correct techniques not only has proven useful with GeMS data but will be valuable on the next generation of Extremely Large Telescopes, where MCAO will be a central technology.

The TMT first light AO facility consists of the Narrow Field Infra-Red AO System (NFIRAOS), the associated Laser Guide Star Facility (LGSF) and the AO Executive Software (AOESW). Design, fabrication and prototyping activities of the TMT first light AO systems and their components have significantly ramped up in Canada, China, France, and in the US. NFIRAOS is an order 60 x 60 laser guide star (LGS) multi-conjugate AO (MCAO) system, which provides uniform, diffraction-limited performance in the J, H, and K bands over 34 x 34 arc sec fields with 50 per cent sky coverage at the galactic pole, as required to support the TMT science cases. NFIRAOS includes two deformable mirrors, six laser guide star wavefront sensors, one high order Pyramid WFS for natural guide star AO, and up to three low-order, IR, natural guide star on-instrument wavefront sensors (OIWFS) and four on-detector guide windows (ODGW) within each client instrument. The first light LGSF system includes six sodium lasers to generate the NFIRAOS laser guide stars.

In this paper, we will provide an update on the progress in designing, prototyping, fabricating and modeling the TMT first light AO systems and their AO components over the last two years. TMT is continuing with detailed AO modeling to support the design and development of the first light AO systems and components. Major modeling topics studied during the last two years include further studies in the area of pyramid wavefront sensing, high precision astrometry, PSF reconstruction for LGS MCAO, LGSF wavefront error budget and sophisticated low order mode temporal filtering.

HARMONI is a visible and NIR integral field spectrograph, providing the E-ELT’s core spectroscopic capability at first light. HARMONI will work at the diffraction limit of the E-ELT, thanks to a Classical and a Laser Tomographic AO system. In this paper, we present the system choices that have been made for these SCAO and LTAO modules. In particular, we describe the strategy developed for the different Wave-Front Sensors: pyramid for SCAO, the LGSWFS concept, the NGSWFS path, and the truth sensor capabilities. We present first potential implementations. And we asses the first system performance.

MICADO is the E-ELT first-light imager, working at the diffraction limit in the near-infrared. Multi-conjugate adaptive optics (MCAO) will be the primary AO mode of MICADO, driving the design of the instrument. It will be provided by MAORY, the E-ELT first-light AO module. MICADO will also come with a SCAO capability, jointly developed by MICADO and MAORY. SCAO will be the first AO mode to be tested at the telescope, in a phased approach of AO integration at the E-ELT.

We present in the following the MICADO-MAORY SCAO specifications, the current SCAO prototyping activities at LESIA for E-ELT scale pyramid wavefront sensor (WFS) and real-time computer (RTC), our activities on end-to-end AO simulations and the current preliminary design of SCAO subsystems. We finish by presenting the implementation and current design studies for the high-contrast imaging mode of MICADO, which will make use of the SCAO correction offered to the instrument.

METIS, the Mid-nfrared E-ELT Imager and Spectrometer, will be providing high-sensitivity imaging and high-resolution spectroscopy in the mid-infrared (3-19 micrometer) to the E-ELT. In order to achieve the exceptional performance required by its driving science cases, exoplanets and proto-planetary disks, METIS will be featuring two Adaptive Optics (AO) systems — a first-light Single Conjugate Adaptive Optics (SCAO) system, complemented by a Laser Tomographic Adaptive Optics (LTAO) system, most likely, a few years after first light. METIS, being one of the three first light science instruments on the European Extremely Large Telescope (E-ELT), will be one of the first instruments using the integrated deformable mirror of the E-ELT for its Adaptive Optics (AO) correction.

The internal SCAO system designed to maximize the performance for bright targets and has its wavefront sensors (WFSs) build inside the METIS cryostat to minimize the number of warm surfaces towards the science detectors. Although the internal dichroic will reflect all light short wards of 3 micrometers towards the WFS, only the IR light will most likely be used, mainly due to the expected improved performance at longer wavelengths for the WFS. A trade-off has been made between both visible versus infrared wave front sensing as well as Pyramid versus Shack-Hartmann, under various observing conditions and target geometries, taking into account performance, target availability, reliability and technology readiness level. The base line for the SCAO system is to minimize system complexity, thereby ensuring system availability and reliability even under first-light conditions.

Since the SCAO system will require a bright guide star near the science target, it can only be used for a limited number of targets. The LTAO system, consisting of up to 6 LGS and up to 3 low-order NGS WFS and located outside the cryostat, is designed to increase the sky coverage on arbitrary targets to >80%. Investigations are ongoing if the internal SCAO system can be used as either a Low-Order WFS or metrology system.

CANARY is an on-sky Laser Guide Star (LGS) tomographic AO demonstrator in operation at the 4.2m William Herschel Telescope (WHT) in La Palma. From the early demonstration of open-loop tomography on a single deformable mirror using natural guide stars in 2010, CANARY has been progressively upgraded each year to reach its final goal in July 2015. It is now a two-stage system that mimics the future E-ELT: a GLAO-driven woofer based on 4 laser guide stars delivers a ground-layer compensated field to a figure sensor locked tweeter DM, that achieves the final on-axis tomographic compensation. We present the overall system, the control strategy and an overview of its on-sky performance.

The Keck Planet Imager and Characterizer (KPIC) is a cost-effective upgrade path to the W.M. Keck observatory (WMKO) adaptive optics (AO) system, building on the lessons learned from first and second-generation extreme AO (ExAO) coronagraphs. KPIC will explore new scientific niches in exoplanet science, while maturing critical technologies and systems for future ground-based (TMT, EELT, GMT) and space-based planet imagers (HabEx, LUVOIR). The advent of fast low-noise IR cameras (IR-APD, MKIDS, electron injectors), the rapid maturing of efficient wavefront sensing (WFS) techniques (Pyramid, Zernike), small inner working angle (IWA) coronagraphs (e.g., vortex) and associated low-order wavefront sensors (LOWFS), as well as recent breakthroughs in high contrast high resolution spectroscopy, open new direct exoplanet exploration avenues that are complementary to planet imagers such as VLT-SPHERE and the Gemini Planet Imager (GPI). For instance, the search and detailed characterization of planetary systems on solar-system scales around late-type stars, mostly beyond SPHERE and GPI's reaches, can be initiated now at WMKO.

The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of ∼4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z < 0.1 universe. RTS will comprise an upgraded version of the Robo-AO laser AO system and will respond quickly to target-of-opportunity events, minimizing the time between discovery and characterization. RTS will acquire simultaneous-multicolor images with an acuity of 0.07–0.10" across the entire visible spectrum (20% i′-band Strehl in median conditions) and <0.16" in the near infrared, and will detect companions at 0.5" at contrast ratio of ∼500. The system will include a high-efficiency prism integral field unit spectrograph: R = 70-140 over a total bandpass of 840–1830nm with an 8.7" by 6.0" field of view (0.15" spaxels). The AO correction boosts the infrared point-source sensitivity of the spectrograph against the sky background by a factor of seven for faint targets, giving the UH 2.2-m the H-band sensitivity of a 5.7-m telescope without AO.

We describe a novel technique atmospheric turbulence monitoring called FASS (full aperture seeing sensor) based on a low noise CCD detector. The method uses a Fourier processing approach that estimates the spatial frequency distribution of the scintillation images. This frequency approach samples the propagated images along pupil rings, making the frequency transformation circular, avoiding distortions due to the finite nature of the data. It is shown that aspects such as detector exposure time, opto-mechanical stability, detailed modelling of propagation, noise and star chromaticity, must be carefully addressed during the design and calibration stages.

Although only ground conjugation results are presented in this article, the technique is expected to operate in the generalized mode guaranteeing sufficiently large speckles (larger than the detector pixels). Pixel gains and offsets are effectively corrected, so they don’t significantly influence the accuracy of the profile estimation. Temporal correlations are also shown to provide complementary information not only on the layer wind velocity, but a coarse estimation of their altitude.

Factors limiting the accuracy of the method, such as chromaticity, turbulence strength, exposure time and vibrations are discussed. The method provides excellent performance in simulations and encouraging preliminary results from on-sky images acquired and Paranal, Chile. Comparison to coetaneous profiles estimated with the Durham Stereo-SCIDAR instrument (DSS) are analysed.

In this contribution we present the most relevant results obtained in the context of a feasibility study (MOSE) undertaken for ESO. The principal aim of the project was to quantify the performances of an atmospherical non-hydrostatical mesoscale model (Astro-Meso-NH code) in forecasting all the main atmospherical parameters relevant for the ground-based astronomical observations and the optical turbulence (C_N² and associated integrated astroclimatic parameters) above Cerro Paranal (site of the VLT) and Cerro Armazones (site of the E-ELT). A detailed analysis on the score of success of the predictive capacities of the system have been carried out for all the astroclimatic as well as for the atmospherical parameters. Considering the excellent results that we obtained, this study proved the opportunity to implement on these two sites an automatic system to be run nightly in an operational configuration to support the scheduling of scientific programs as well as of astronomical facilities (particularly those supported by AO systems) of the VLT and the E-ELT. At the end of 2016 a new project for the implementation of a demonstrator of an operational system to be run on the two ESO's sites will start. The fact that the system can be run simultaneously on the two sites is an ancillary appealing feature of the system. Our team is also responsible for the implementation of a similar automatic system at Mt.Graham, site of the LBT (ALTA Project). Our system/method will permit therefore to make a step ahead in the framework of the Service Mode for new generation telescopes. Among the most exciting achieved results we cite the fact that we proved to be able to forecast C_N² profiles with a vertical resolution as high as 150 m. Such a feature is particularly crucial for all WFAO systems that require such detailed information on the OT vertical stratification on the whole 20 km above the ground. This important achievement tells us that all the WFAO systems can rely on automatic systems that are able to support their optimized use.

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument, under development for the Subaru Telescope, has currently the fastest on-sky wavefront control loop, with a pyramid wavefront sensor running at 3.5 kHz. But even at that speed, we are still limited by low-frequency vibrations. The current main limitation was found to be vibrations attributed mainly to the rotation of the telescope. Using the fast wavefront sensors, cameras and accelerometers, we managed to identify the origin of most of the vibrations degrading our performance. Low-frequency vibrations are coming from the telescope drive in azimuth and elevation, as well as the elevation encoders when the target is at transit. Other vibrations were found at higher frequency coming from the image rotator inside Subaru's adaptive optics facility AO188.

Different approaches are being implemented to take care of these issues. The PID control of the image rotator has been tuned to reduce their high-frequency contribution. We are working with the telescope team to tune the motor drives and reduce the impact of the elevation encoder. A Linear Quadratic Gaussian controller (LQG, or Kalman filter) is also being implemented inside SCExAO to control these vibrations. These solutions will not only improve significantly SCExAOs performance, but will also help all the other instruments on the Subaru Telescope, especially the ones behind AO188. Ultimately, this study will also help the development of the TMT, as these two telescopes share very similar drives.

If the Real-Time Computer is the heart of an AO system, the Wavefront Sensor (WFS) its eyes, the Deformable Mirror (DM) its hands and the control strategy its nervous system, the sum of all those parts is made into a harmonious entity thanks to calibrations. This paper does not have the ambition to provide an overview of all the currently existing calibration strategies, but rather to focus on a few challenging problems and their recent evolution in the era of adaptive telescopes, mostly based on the experience of ESO's Adaptive Optics Instruments in general and the AO Facility in particular.

Single most important calibration in post-focal AO system, the recording of the Interaction Matrix (IM) between WFS and DM has since long evolved to use fast modulation techniques, has shown to be feasible on-sky and is now almost free from measurements thanks to its pseudo-synthetic generation, quasi-mandatory solution in an adaptive telescope. Pseudo- because it requires an unprecedented knowledge of the components' characteristics, especially the WFS, DM and the optical registration between the two.

Bigger telescopes and the use of Laser Guide Stars (LGS) also mean that the properties of the system will change in time and thus need to be constantly updated thanks to online diagnosis tools for spot size measurement, atmosphere monitoring, Wavefront Sensing and control optimization. New loops come into play like the one to minimize LGS Jitter and the one taking over the telescope active optics by means of offloading the DM low orders, and they all require calibration. More calibration means more time and one has to carefully balance the calibrations that require precious telescope night time, day time or for the best, no telescope time at all. Their importance sometimes underestimated, calibrations have repeatedly shown to be a vital part in the optimum functioning of present and future AO systems.

This paper presents some aspects of the calibration plan that has been developed for NFIRAOS, the TMT first light MCAO system. The plan consolidates the best practices from current 8-meter class AO instruments, while also addressing the specificities of NFIRAOS. We present the calibration hardware that will be available in NFIRAOS, including artificial sources, diagnostic detectors and supporting software. We then discuss two key calibration procedures in more details: the measurement of the DM-WFS interaction matrix and the multi-conjugate AO correction of the NFIRAOS non-common path aberration.

AO optimal control relies centrally on a stochastic model of the turbulence. Models based on both Cn2 spatial priors and temporal dynamics have been used for LQG control for both SCAO and MOAO systems. In this work, we propose turbulence models that account for both wind norm and direction, combining a wind direction-dependent displacement operator with the "boiling turbulence" assumption. We define two extrapolation strategies to complete this new model, and we compare their performance with the LQG control based solely on wind norm priors, through frozen flow simulations. Finally, we discuss about the application of this formalism to WFAO systems.

Over the last decade, adaptive optics has become essential in different fields of research including medicine and industrial applications. With this new need, the market of deformable mirrors has expanded a lot allowing new technologies and actuation principles to be developed. Several E-ELT instruments have identified the need for post focal deformable mirrors but with the increasing size of the telescopes the requirements on the deformable mirrors become more demanding. A simple scaling up of existing technologies from few hundred actuators to thousands of actuators will not be sufficient to satisfy the future needs of ESO. To bridge the gap between available deformable mirrors and the future needs for the E-ELT, ESO started a development program for deformable mirror technologies. The requirements and the path to get the deformable mirrors for post focal adaptive optics systems for the E-ELT is presented.

This paper presents the design and the realisation of a technique to attenuate the hysteresis nonlinear phenomenon of piezoelectric actuators. Piezoelectric actuator are widely utilised for deformable mirrors used for MOAO and power laser beam shaping techniques. The nonlinearities of piezo are usually iteratively compensa- ted using closed-loop set-ups. In open-loop control, the hysteresis and the creep of the piezo cannot be corrected, thus this nonlinearities must be removed or at least minimised. The concept has been demonstrated on high displacement Amplified Piezoelectric Actuators (APA) mounted in a Fabry-Perot interferometer. The hysteresis attenuation technique aims to assist the Fabry-Perots nano-positioning control system to attain its main scientific specification. In such system, each APA has a maximum stroke of 270 μm within a 170 V (-20 V to +150 V) range and is used to position a high reflective mirror plate. The Fabry-Perots nano-positioning control system is specified to limit the APAs positioning steady-state noise to 3nm rms, but the hysteresis limits the positioning accuracy. In order to attenuate hysteresis, a hybrid amplifier circuit built with a high power operational amplifier has been designed and applied for each APA. The experiments results show that the hysteresis effect has almost been eliminated, and consequently the positioning steady-state noise can significantly been reduced. Because of the excellent results of this hybrid amplifier, a patent application has been introduced in June 12, 2015 under number No.1555381 and is being reviewed now.

This paper recalls the history of sodium guide star laser systems used in astronomy and space situational awareness adaptive optics, analyzing the impact that sodium laser technology evolution has had on routine telescope operations. While it would not be practical to describe every single sodium guide star laser system developed to date, it is possible to characterize their evolution in broad technology terms. The first generation of sodium lasers used dye laser technology to create the first sodium laser guide stars in Hawaii, California, and Spain in the late 1980s and 1990s. These experimental systems were turned into the first laser guide star facilities to equip mediumto- large diameter adaptive optics telescopes, opening a new era of Laser Guide Star Adaptive Optics (LGS AO)-enabled diffraction-limited imaging from the ground. Although they produced exciting scientific results, these laser guide star facilities were large, power-hungry and messy. In the USA, a second-generation of sodium lasers was developed in the 2000s that used cleaner, yet still large and complex, solid-state laser technology. These are the systems in routine operation at the 8 to 10m-class astronomical telescopes and 4m-class satellite imaging facilities today. Meanwhile in Europe, a third generation of sodium lasers was being developed using inherently compact and efficient fiber laser technology, and resulting in the only commercially available sodium guide star laser system to date. Fiber-based sodium lasers are being or will soon be deployed at three astronomical telescopes and two space surveillance stations. These highly promising systems are still relatively large to install on telescopes and they remain significantly expensive to procure and maintain. We are thus proposing to develop a fourth generation of sodium lasers: based on semiconductor technology, these lasers could provide a definitive solution to the problem of sodium LGS AO laser sources for all astronomy and space situational awareness applications.

The Keck II Laser Guide Star (LGS) Adaptive Optics (AO) System was upgraded from a dye laser to a TOPTICA/MPBC Raman-Fibre Amplification (RFA) laser in December 2015. The W. M. Keck Observatory (WMKO) has been operating its AO system with a LGS for science since 2004 using a first generation 15 W dye laser. Using the latest diode pump laser technology, Raman amplification, and a well-tuned second harmonic generator (SHG), this Next Generation Laser (NGL) is able to produce a highly stable 589 nm laser beam with the required power, wavelength and mode quality. The beam’s linear polarization and continuous wave format along with optical back pumping are designed to improve the sodium atom coupling efficiency over previously operated sodium-wavelength lasers. The efficiency and operability of the new laser has also been improved by reducing its required input power and cooling, size, and the manpower to operate and maintain it.

The new laser has been implemented on the telescope’s elevation ring with its electronics installed on a new Nasmyth sub-platform, with the capacity to support up to three laser systems for future upgrades. The laser is projected from behind the telescope’s secondary mirror using the recently implemented center launch system (CLS) to reduce LGS spot size. We will present the new laser system and its performance with respect to power, stability, wavelength, spot size, optical repumping, polarization, efficiency, and its return with respect to pointing alignment to the magnetic field. Preliminary LGSAO performance is presented with the system returning to science operations. We will also provide an update on current and future upgrades at the WMKO.

The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument aims at detecting extremely faint sources (giant extrasolar planets) in the vicinity of bright stars¹. Such a challenging goal requires the use of a very-high-order performance Adaptive Optics [AO] system feeding the scientific instruments with a quasi-perfect flat wave front corrected from all the atmospheric turbulence and internal defects. This AO system, called SAXO (Sphere Ao for eXoplanet Observation) is the heart of the instrument, a heart beating 1200 time per second and providing unprecedented image quality for a large ground based telescope at optical/near infrared wavelength. We will present the latest results obtained on-sky, demonstrating its exceptional performance (in terms of correction quality, stability and robustness) and tremendous potentiality for high contrast imaging and more specifically for exoplanet discovery.

The Gemini Planet Imager is a high-contrast near-infrared instrument specifically designed to image exoplanets and circumstellar disks over a narrow field of view. We use science data and AO telemetry taken during the first 1.5 yr of the GPI Exoplanet Survey to quantify the performance of the AO system. In a typical 60 sec H-band exposure, GPI achieves a 5σ raw contrast of 10⁻⁴ at 0.4"; typical final 5σ contrasts for full 1 hr sequences are more than 10 times better than raw contrasts. We find that contrast is limited by bandwidth wavefront error over much of the PSF. Preliminary exploratory factor analysis can explain 60{70% of the variance in raw contrasts with combinations of seeing and wavefront error metrics. We also examine the effect of higher loop gains on contrast by comparing wavefront error maps reconstructed from AO telemetry to concurrent IFS images. These results point to several ways that GPI performance could be improved in software or hardware.

SCExAO is the premier high-contrast imaging platform for the Subaru Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K band) with stable pointing and coronagraphs with extremely small inner working angles, optimized for imaging faint companions very close to the host. In the visible, it has several interferometric imagers which offer polarimetric and spectroscopic capabilities. A recent addition is the RHEA spectrograph enabling spatially resolved high resolution spectroscopy of the surfaces of giant stars, for example. New capabilities on the horizon include post-coronagraphic spectroscopy, spectral differential imaging, nulling interferometry as well as an integral field spectrograph and an MKID array. Here we present the new modules of SCExAO, give an overview of the current commissioning status of each of the modules and present preliminary results.

Adaptive Optics (AO) that compensates for atmospheric turbulence is a standard tool for high angular resolution observations of the Sun at most ground-based observatories today. AO systems as deployed at major solar telescopes allow for diffraction limited resolution in the visible light regime. Anisoplanatism of the turbulent air volume limits the effectivity of classical AO to a small region, typically of order 10 seconds of arc. Scientifically interesting features on the solar surface are often larger thus multi-conjugate adaptive optics (MCAO) is being developed to enlarge the corrected field of view. Dedicated wavefront sensors for observations of solar prominences off the solar limb with AO have been deployed. This paper summarizes wavefront sensing concepts specific to solar adaptive optics applications, like the correlating Shack-Hartmann wavefront sensor (SH-WFS), multi-directional sensing with wide-field SH-WFSs, and gives a brief overview of recent developments.

When the Daniel K. Inouye Solar Telescope (DKIST) achieves first light in 2019, it will deliver the highest spatial resolution images of the solar atmosphere ever recorded. Additionally, the DKIST will observe the Sun with unprecedented polarimetric sensitivity and spectral resolution, spurring a leap forward in our understanding of the physical processes occurring on the Sun.

The DKIST wavefront correction system will provide active alignment control and jitter compensation for all six of the DKIST science instruments. Five of the instruments will also be fed by a conventional adaptive optics (AO) system, which corrects for high frequency jitter and atmospheric wavefront disturbances. The AO system is built around an extended-source correlating Shack-Hartmann wavefront sensor, a Physik Instrumente fast tip-tilt mirror (FTTM) and a Xinetics 1600-actuator deformable mirror (DM), which are controlled by an FPGA-based real-time system running at 1975 Hz. It is designed to achieve on-axis Strehl of 0.3 at 500 nm in median seeing (r₀ = 7 cm) and Strehl of 0.6 at 630 nm in excellent seeing (r₀ = 20 cm).

The DKIST wavefront correction team has completed the design phase and is well into the fabrication phase. The FTTM and DM have both been delivered to the DKIST laboratory in Boulder, CO. The real-time controller has been completed and is able to read out the camera and deliver commands to the DM with a total latency of approximately 750 μs. All optics and optomechanics, including many high-precision custom optics, mounts, and stages, are completed or nearing the end of the fabrication process and will soon undergo rigorous acceptance testing.

Before installing the wavefront correction system at the telescope, it will be assembled as a testbed in the laboratory. In the lab, performance tests beginning with component-level testing and continuing to full system testing will ensure that the wavefront correction system meets all performance requirements. Further work in the lab will focus on fine-tuning our alignment and calibration procedures so that installation and alignment on the summit will proceed as efficiently as possible.

The Adaptive Optics Facility is an ESO project aiming at converting Yepun, one of the four 8m telescopes in Paranal, into an adaptive telescope. This is done by replacing the current conventional secondary mirror of Yepun by a Deformable Secondary Mirror (DSM) and attaching four Laser Guide Star (LGS) Units to its centerpiece. In the meantime, two Adaptive Optics (AO) modules have been developed incorporating each four LGS WaveFront Sensors (WFS) and one tip-tilt sensor used to control the DSM at 1 kHz frame rate. The four LGS Units and one AO module (GRAAL) have already been assembled on Yepun.

Besides the technological challenge itself, one critical area of AOF is the AO control strategy and its link with the telescope control, including Active Optics used to shape M1. Another challenge is the request to minimize the overhead due to AOF during the acquisition phase of the observation.

This paper presents the control strategy of the AOF. The current control of the telescope is first recalled, and then the way the AO control makes the link with the Active Optics is detailed. Lab results are used to illustrate the expected performance. Finally, the overall AOF acquisition sequence is presented as well as first results obtained on sky with GRAAL.

This paper presents the AO performance we got on-sky with RAVEN, a Multi-Object Adaptive Optics (MOAO) technical and science demonstrator installed and tested at the Subaru telescope. We report Ensquared-Energy (EE) and Full Width at Half Maximum (FWHM) measured from science images on Subaru's IRCS taken during all of the on-sky observing runs. We show these metrics as function of different AO modes and atmospheric conditions for two asterisms of natural guide stars. The performances of the MOAO and Ground-Layer AO (GLAO) modes are between the classical Single-Conjugate AO (SCAO) and seeing-limited modes. We achieve the EE of 30% in H-band with the MOAO correction, which is a science requirement for RAVEN. The MOAO provides sightly better performance than the GLAO mode in both asterisms. One of the reasons which cause this small difference between the MOAO and GLAO modes may be the strong GL contribution. Also, the performance of the MOAO modes is affected by the accuracy of the on-sky turbulence profiling by the SLOpe Detection And Ranging (SLODAR) method.

The Research School of Astronomy and Astrophysics have been developing adaptive optics systems for space situational awareness. As part of this program we have developed satellite imaging using compact adaptive optics systems for small (1-2 m) telescopes such as those operated by Electro Optic Systems (EOS) from the Mount Stromlo Observatory. We have focused on making compact, simple, and high performance AO systems using modern high stroke high speed deformable mirrors and EMCCD cameras. We are able to track satellites down to magnitude 10 with a Strehl in excess of 20% in median seeing.

In 2007 ESO started a program at SELEX (now LEONARDO) to develop noiseless near infrared HgCdTe electron avalanche photodiode arrays (eAPD)[1][2][3]. This eAPD technology is only way to overcome the limiting CMOS noise barrier of near infrared sensors used for wavefront sensing and fringe tracking. After several development cycles of solid state engineering techniques which can be easily applied to the chosen growth technology of metal organic vapour phase epitaxy (MOVPE), the eAPD arrays have matured and resulted in the SAPHIRA arrays. They have a format of 320x256 pixels with a pitch of 24 μm. They now offer an unmatched combination of sub-electron read noise at millisecond frame readout rates. The first generation of SAPHIRA arrays were only sensitive in H and K-band. With the removal of a wide bandgap buffer layer the arrays are now sensitive from λ=0.8 μm to 2.5 μm with high quantum efficiency over the entire wavelength range. The high temperature anneal applied during the growth process produces material with superb cosmetic quality at an APD gain of over 600. The design of the SAPHIRA ROIC has also been revised and the new ME1000 ROIC has an optimized analogue chain and more flexible readout modes. The clock for the vertical shift register is now under external control. The advantage of this is that correlated-double-sampling and uncorrelated readout in the rolling shutter mode now have a duty cycle of 100% at the maximum frame rate. Furthermore, to reduce the readout noise rows can be read several times before and after row reset. Since the APD gain is sufficiently high that one photon produces many more electrons than the square root of kTC which is the charge uncertainty after reset, signals of one photon per exposure can be easily detected without the need for double correlated sampling. First results obtained with the fringe tracker in GRAVITY and the four SAPHIRA wavefront sensors installed in the CIAO adaptive optics systems of the four 8 meter telescopes of the VLTI have proven the unrivaled performance of the SAPHIRA eAPD technology. A future program is being assembled to develop eAPD arrays having a larger format of 1Kx1K capable of frame rates of 1.2 KHz. There are also good prospects to offer low dark current eAPD technology for large format science focal planes as well.

First Light Imaging's CRED-ONE infrared camera is capable of capturing up to 3500 full frames per second with a subelectron readout noise. This breakthrough has been made possible thanks to the use of an e-APD infrared focal plane array which is a real disruptive technology in imagery. We will show the performances of the camera, its main features and compare them to other high performance wavefront sensing cameras like OCAM2 in the visible and in the infrared. The project leading to this application has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement N° 673944.

ESO has a very active on-going AO WFS detector development program to not only meet the needs of the current crop of instruments for the VLT, but also has been actively involved in gathering requirements, planning, and developing detectors and controllers/cameras for the instruments in design and being proposed for the E-ELT.

This paper provides an overall summary of the AO WFS Detector requirements of the E-ELT instruments currently in design and telescope focal units. This is followed by a description of the many interesting detector, controller, and camera developments underway at ESO to meet these needs; a) the rationale behind and plan to upgrade the 240x240 pixels, 2000fps, “zero noise”, L3Vision CCD220 sensor based AONGC camera; b) status of the LGSD/NGSD High QE, 3e- RoN, fast 700fps, 1760x1680 pixels, Visible CMOS Imager and camera development; c) status of and development plans for the Selex SAPHIRA NIR eAPD and controller.

Most of the instruments and detector/camera developments are described in more detail in other papers at this conference.

We discuss the advantages of wavefront sensing at near-infrared (IR) wavelengths with low-noise detector technologies that have recently become available. In this paper, we consider low order sensing with laser guide star (LGS) adaptive optics (AO) and high order sensing with natural guide star (NGS) AO. We then turn to the application of near-IR sensing with the W. M. Keck Observatory (WMKO) AO systems for science and as a demonstrator for similar systems on extremely large telescopes (ELTs). These demonstrations are based upon an LGS AO near-IR tip-tilt-focus sensor and our collaboration to implement a near-IR pyramid wavefront sensor (PWFS) for a NGS AO L-band coronagraphic imaging survey to identify exoplanet candidates.

SPHERE is the VLT second generation planet hunter instrument. Installed since May 2014 on UT3, the system has been commissioned and verified for more than one year now and routinely delivers unprecedented images of star surroundings, exoplanets and dust disks. The exceptional performance required for this kind of observation makes the appointment: a repeatable Strehl Ratio of 90% in H band, a rough contrast level of 10-5@0.5 arcsec, and reaches 10-6 at the same separation after differential imaging (SDI, ADI). The instrument also presents high contrast levels in the visible and an unprecedented 17mas diffraction-limited resolution at 0.65 microns wavelength. SAXO is the SPHERE XAO system, allowing the system to reach its final detectivity. Its high performance and therefore highly sensitive capacities turns a new eye on telescope environment. Even if XAO performance are reached as expected, some unexpected limitations are here described and a first work around is proposed and discussed. Spatial limitation: wave-front aberrations have been identified, deviating from kolmogorov statistics, and therefore not easily seen and compensated for by the XAO system. The impact of this limitations results in a degraded performance in some particular low wind conditions. Solutions are developed and tested on sky to propose a new operation procedure reducing this limitation. Temporal limitation: high amplitude vibrations on the low order modes have been issued, due to telescope environment and XAO behaviour. Again, a solution is developed and an assessment of its performance is dressed. The potential application of these solutions to E-ELT is proposed.

We present measurements of the evolutionary timescales of speckles around adaptive optics-corrected PSFs. We placed a SELEX SAPHIRA HgCdTe detector behind the SCExAO instrument at Subaru Telescope. We analyzed the behavior of speckles at radial distances of 2-8 λ/D away from the diffraction-limited PSF in H-band (∼1.6μm) images collected at ∼1 kHz framerates. Speckles evolve with a variety of timescales, and these have not previously been studied at near-infrared wavelengths. Ultimately we would like to image reflected-light exoplanets, which necessitates a fast speckle control loop. Based on our measurements, we calculate the parameters of an optimized control loop that would enable such observations.

The AO progresses for astronomy in the Key Laboratory of Adaptive Optics, Chinese Academy of Sciences are reported in this presentation. For night-time astronomical observations, the recent AO technological developments, such as Laser Guide Star, Pyramid Sensor and Deformable Secondary Mirror, are introduced. The solar AO researches are also presented for day-time astronomical observations. Furthermore, we will show the on-sky high resolution observational results in the 1.8m telescope at Gaomeigu site, Yunnan Observatory and the 1-m New Vacuum Solar Telescope (NVST) at Fuxian Lake Solar Observatory respectively.

We have started an initial three-year deployment of Robo-AO at the 2.1-m telescope at Kitt Peak, Arizona as of November 2015. We report here on the project status and two new developments with the Robo-AO KP system: the commissioning of a sub-electron readnoise SAPHIRA near-infrared camera, which will allow us to widen the scope of possible targets to low-mass stellar and substellar objects; and, performance analysis and tuning of the adaptive optics system, which will improve the sensitivity to these objects. Commissioning of the near-infrared camera and optimizing the AO performance occur in parallel with ongoing visible-light science programs.

ERIS is the new AO instrument for VLT-UT4 led by a Consortium of Max-Planck Institut fuer Extraterrestrische Physik, UK-ATC, ETH-Zurich, ESO and INAF. The ERIS AO system provides NGS mode to deliver high contrast correction and LGS mode to extend high Strehl performance to large sky coverage. The AO module includes NGS and LGS wavefront sensors and, with VLT-AOF Deformable Secondary Mirror and Laser Facility, will provide AO correction to the high resolution imager NIX (1–5um) and the IFU spectrograph SPIFFIER (1–2.5um). In this paper we present the preliminary design of the ERIS AO system and the estimated correction performance.

Since the beginning of the development of the Gran Telescopio Canarias (GTC), an Adaptive Optics (AO) system was considered necessary to exploit the full diffraction-limited potential of the telescope. The GTC AO system designed during the last years is based on a single deformable mirror conjugated to the telescope pupil, and a Shack-Hartmann wavefront sensor with 20 x 20 subapertures, using an OCAM2 camera. The GTCAO system will provide a corrected beam with a Strehl Ratio (SR) of 0.65 in K-band with bright natural guide stars.

Most of the subsystems have been manufactured and delivered. The upgrade for the operation with a Laser Guide Star (LGS) system has been recently approved. The present status of the GTCAO system, currently in its laboratory integration phase, is summarized in this paper.

An adaptive optics system (AOS), which consists of a 73-element piezoelectric deformable secondary mirror (DSM), a 9x9 Shack-Hartmann wavefront sensor and a real time controller has been integrated on the 1.8m telescope at the Gaomeigu site of Yunnan Astronomical Observatory, Chinese Academy of Sciences. Compared to the traditional AOS on Coude focus, the DSM AOS adopts much less reflections and consequently restrains the thermal noise and increases the energy transmitting to the system. Before the first on-sky test, this system has been demonstrated in the laboratory by compensating the simulated atmospheric turbulence generated by a rotating phase screen. A new multichannel-modulation calibration method which is used to measure the DSM based AOS interaction matrix is proposed. After integration on the 1.8m telescope, the closed-loop compensation of the atmospheric turbulence with the DSM based AOS is achieved, and the first light results from the on-sky experiment are reported.

We review astronomical results in the visible (λ<1μm) with adaptive optics. Other than a brief period in the early 1990s, there has been little (<1 paper/yr) night-time astronomical science published with AO in the visible from 2000–2013 (outside of the solar or Space Surveillance Astronomy communities where visible AO is the norm, but not the topic of this invited review). However, since mid-2013 there has been a rapid increase visible AO with over 50 refereed science papers published in just ∼2.5 years (visible AO is experiencing a rapid growth rate very similar to that of NIR AO science from 1997–2000; Close 2000). Currently the most productive small (D < 2 m) visible light AO telescope is the UV-LGS Robo-AO system (Baranec, et al. 2016) on the robotic Palomar D=1.5 m telescope (currently relocated to the Kitt Peak 1.8m; Salama et al. 2016). Robo-AO uniquely offers the ability to target >15 objects/hr, which has enabled large (>3000 discrete targets) companion star surveys and has resulted in 23 refereed science publications. The most productive large telescope visible AO system is the D=6.5m Magellan telescope AO system (MagAO). MagAO is an advanced Adaptive Secondary Mirror (ASM) AO system at the Magellan 6.5m in Chile (Morzinski et al. 2016). This ASM secondary has 585 actuators with < 1 msec response times (0.7 ms typically). MagAO utilizes a 1 kHz pyramid wavefront sensor. The relatively small actuator pitch (∼22 cm/subap) allows moderate Strehls to be obtained in the visible (0.63–1.05 microns). Long exposures (60s) achieve <30mas resolutions, 30% Strehls at 0.62 microns (r') with the VisAO camera in 0.5” seeing with bright R ≤ 9 mag stars. These capabilities have led to over 22 MagAO refereed science publications in the visible. The largest (D=8m) telescope to achieve regular visible AO science is SPHERE/ZIMPOL. ZIMPOL is a polarimeter fed by the ∼1.2 kHz SPHERE ExAO system (Fusco et al. 2016). ZIMPOL's ability to differentiate scattered polarized light from starlight allows the sensitive detection of circumstellar disks, stellar surfaces, and envelopes of evolved AGB stars. Here we review the key steps to having good performance in the visible and review the exciting new AO visible science opportunities and science results in the fields of: exoplanet detection; circumstellar and protoplanetary disks; young stars; AGB stars; emission line jets; and stellar surfaces. The recent rapid increase in the scientific publications and power of visible AO is due to the maturity of the next-generation of AO systems and our new ability probe circumstellar regions with very high (10–30 mas) spatial resolutions that would otherwise require much larger (>10m) diameter telescopes in the infrared.

With the aim of paving the road for future accurate astrometry with MICADO at the European-ELT, we performed an astrometric study using two different but complementary approaches to investigate two critical components that contribute to the total astrometric accuracy. First, we tested the predicted improvement in the astrometric measurements with the use of an atmospheric dispersion corrector (ADC) by simulating realistic images of a crowded Galactic globular cluster. We found that the positional measurement accuracy should be improved by up to ∼ 2 mas with the ADC, making this component fundamental for high-precision astrometry. Second, we analysed observations of a globular cluster taken with the only currently available Multi-Conjugate Adaptive Optics assisted camera, GeMS/GSAOI at Gemini South. Making use of previously measured proper motions of stars in the field of view, we were able to model the distortions affecting the stellar positions. We found that they can be as large as ∼ 200 mas, and that our best model corrects them to an accuracy of ∼ 1 mas. We conclude that future astrometric studies with MICADO requires both an ADC and an accurate modelling of distortions to the field of view, either through an a-priori calibration or an a-posteriori correction.

First on sky adaptive optics experiments were performed on the Dunn Solar Telescope on 1979, with a shearing interferometer and limited success. Those early solar adaptive optics efforts forced to custom-develop many components, such as Deformable Mirrors and WaveFront Sensors, which were not available at that time. Later on, the development of the correlation Shack-Hartmann marked a breakthrough in solar adaptive optics. Since then, successful Single Conjugate Adaptive Optics instruments have been developed for many solar telescopes, i.e. the National Solar Observatory, the Vacuum Tower Telescope and the Swedish Solar Telescope. Success with the Multi Conjugate Adaptive Optics systems for GREGOR and the New Solar Telescope has proved to be more difficult to attain. Such systems have a complexity not only related to the number of degrees of freedom, but also related to the specificities of the Sun, used as reference, and the sensing method. The wavefront sensing is performed using correlations on images with a field of view of 10", averaging wavefront information from different sky directions, affecting the sensing and sampling of high altitude turbulence. Also due to the low elevation at which solar observations are performed we have to include generalized fitting error and anisoplanatism, as described by Ragazzoni and Rigaut, as non-negligible error sources in the Multi Conjugate Adaptive Optics error budget. For the development of the next generation Multi Conjugate Adaptive Optics systems for the Daniel K. Inouye Solar Telescope and the European Solar Telescope we still need to study and understand these issues, to predict realistically the quality of the achievable reconstruction. To improve their designs other open issues have to be assessed, i.e. possible alternative sensing methods to avoid the intrinsic anisoplanatism of the wide field correlation Shack-Hartmann, new parameters to estimate the performance of an adaptive optics solar system, alternatives to the Strehl and the Point Spread Function used in night time adaptive optics but not really suitable to the solar systems, and new control strategies more complex than the ones used in nowadays solar Multi Conjugate Adaptive Optics systems. In this paper we summarize the lessons learned with past and current solar adaptive optics systems and focus on the discussion on the new alternatives to solve present open issues limiting their performance.

MOSAIC is the proposed multiple-object spectrograph for the E-ELT that will utilise the widest possible field of view provided by the telescope. In terms of adaptive optics, there are two distinct operating modes required to meet the top-level science requirements. The MOSAIC High Multiplex Mode (HMM) requires either seeing-limited or GLAO correction within a 0.6 (NIR) and 0.9 (VIS) arcsecond sub-fields over the widest possible field for a few hundred objects. To achieve seeing limited operation whilst maintaining the maximum unvignetted field of view for scientific observation will require recreating some of the functionality present in the Pre-Focal Station relating to control of the E-ELT active optics. MOSAIC High Definition Mode Control (HDM) requires a 25% Ensquared Energy (EE) within 150mas in the H-band element for approximately 10 targets distributed across the full E-ELT field, implying the use of Multiple Object AO (MOAO). Initial studies have shown that to meet the EE requirements whilst maintaining high-sky coverage will require the combination of wavefront signals from both high-order NGS and LGS to provide a tomographic estimate for the correction to be applied to the open-loop MOAO DMs. In this paper we present the current MOSAIC AO design and provide the first performance estimates for the baseline instrument design. We then report on the various trade-offs that will be investigated throughout the course of the Phase A study, such as the requirement to mix NGS and LGS signals tomographically. Finally, we discuss how these will impact the AO architecture, the MOSAIC design and ultimately the scientific performance of this wide-field workhorse instrument at the E-ELT.

For today and future adaptive optics observations, sodium laser guide stars (LGSs) are crucial; however, the LGS elongation problem due to the sodium layer has to be compensated, in particular for extremely large telescopes. In this paper, we describe the concept of truth wavefront sensing as a solution and present its design using a pyramid wavefront sensor (PWFS) to improve NFIRAOS (Narrow Field InfraRed Adaptive Optics System), the first light adaptive optics system for Thirty Meter Telescope. We simulate and test the truth wavefront sensor function under a controlled environment using the HeNOS (Herzberg NFIRAOS Optical Simulator) bench, a scaled-down NFIRAOS bench at NRC-Herzberg. We also touch on alternative pyramid component options because despite recent high demands for PWFSs, we suffer from the lack of pyramid supplies due to engineering difficulties.

Outer scale is a relevant parameter for the experimental performance evaluation of large telescopes. Different techniques have been used for the outer scale estimation. In situ measurements with radiosounding balloons have given very small values of outer scale. This latter has also been estimated directly at the ground level from the wavefront analysis with High Angular Resolution (HAR) techniques using interferometric or Shack-Hartmann or more generally AO systems data. Dedicated instruments have been also developed for the outer scale monitoring such as the Generalized Seeing Monitor (GSM) and the Monitor of Outer Scale Profile (MOSP). The measured values of outer scale from HAR techniques, GSM and MOSP are somewhat coherent and are larger than the in situ results. The main explanation of this difference comes from the definition of the outer scale itself.

This paper aims to give a review in a non-exhaustive way of different techniques and instruments for the measurement of the outer scale. Comparisons of outer scale measurements will be discussed in the light of the different definitions of this parameter, the associated observable quantities and the atmospheric turbulence model as well.

There is a strong need to model the temporal fluctuations in turbulence parameters, for instance for scheduling, simulation and prediction purposes. This paper aims at modelling the dynamic behaviour of the turbulence coherence length r₀, utilising measurement data from the Stereo-SCIDAR instrument installed at the Isaac Newton Telescope at La Palma. Based on an estimate of the power spectral density function, a low order stochastic model to capture the temporal variability of r₀ is proposed. The impact of this type of stochastic model on the prediction of the coherence length behaviour is shown.

Vertical profiles of the atmospheric optical turbulence strength and velocity is of critical importance for simulating, designing, and operating the next generation of instruments for the European Extremely Large Telescope. Many of these instruments are already well into the design phase meaning these profies are required immediately to ensure they are optimised for the unique conditions likely to be observed.

Stereo-SCIDAR is a generalised SCIDAR instrument which is used to characterise the profile of the atmospheric optical turbulence strength and wind velocity using triangulation between two optical binary stars. Stereo-SCIDAR has demonstrated the capability to resolve turbulent layers with the required vertical resolution to support wide-field ELT instrument designs. These high resolution atmospheric parameters are critical for design studies and statistical evaluation of on-sky performance under real conditions. Here we report on the new Stereo-SCIDAR instrument installed on one of the Auxillary Telescope ports of the Very Large Telescope array at Cerro Paranal. Paranal is located approximately 20 km from Cerro Armazones, the site of the E-ELT. Although the surface layer of the turbulence will be different for the two sites due to local geography, the high-altitude resolution profiles of the free atmosphere from this instrument will be the most accurate available for the E-ELT site.

In addition, these unbiased and independent profiles are also used to further characterise the site of the VLT. This enables instrument performance calibration, optimisation and data analysis of, for example, the ESO Adaptive Optics facility and the Next Generation Transit Survey. It will also be used to validate atmospheric models for turbulence forecasting. We show early results from the commissioning and address future implications of the results.

General relativity can be tested in the strong gravity regime by monitoring stars orbiting the supermassive black hole at the Galactic Center with adaptive optics. However, the limiting source of uncertainty is the spatial PSF variability due to atmospheric anisoplanatism and instrumental aberrations. The Galactic Center Group at UCLA has completed a project developing algorithms to predict PSF variability for Keck AO images. We have created a new software package (AIROPA), based on modified versions of StarFinder and Arroyo, that takes atmospheric turbulence profiles, instrumental aberration maps, and images as inputs and delivers improved photometry and astrometry on crowded fields. This software package will be made publicly available soon.

One of the primary scientific limitations of adaptive optics (AO) has been the incomplete knowledge of the point spread function (PSF), which has made it difficult to use AO for accurate photometry and astrometry in both crowded and sparse fields, for extracting intrinsic morphologies and spatially resolved kinematics, and for detecting faint sources in the presence of brighter sources. To address this limitation, we initiated a program to determine and demonstrate PSF reconstruction for science observations obtained with Keck AO. This paper aims to give a broad view of the progress achieved in implementing a PSF reconstruction capability for Keck AO science observations.

This paper describes the implementation of the algorithms, and the design and development of the prototype operational tools for automated PSF reconstruction. On-sky performance is discussed by comparing the reconstructed PSFs to the measured PSF’s on the NIRC2 science camera. The importance of knowing the control loop performance, accurate mapping of the telescope pupil to the deformable mirror and the science instrument pupil, and the telescope segment piston error are highlighted. We close by discussing lessons learned and near-term future plans.

CANARY is an open-loop tomographic adaptive optics (AO) demonstrator that was designed for use at the 4.2m William Herschel Telescope (WHT) in La Palma. Gearing up to extensive statistical studies of high redshifted galaxies surveyed with Multi-Object Spectrographs (MOS), the demonstrator CANARY has been designed to tackle technical challenges related to open-loop Adaptive-Optics (AO) control with mixed Natural Guide Star (NGS) and Laser Guide Star (LGS) tomography.

We have developed a Point Spread Function (PSF)-Reconstruction algorithm dedicated to MOAO systems using system telemetry to estimate the PSF potentially anywhere in the observed field, a prerequisite to deconvolve AO-corrected science observations in Integral Field Spectroscopy (IFS). Additionally the ability to accurately reconstruct the PSF is the materialization of the broad and fine-detailed understanding of the residual error contributors, both atmospheric and opto-mechanical.

In this paper we compare the classical PSF-r approach from Véran (¹) that we take as reference on-axis using the truth-sensor telemetry to one tailored to atmospheric tomography by handling the off-axis data only.

We've post-processed over 450 on-sky CANARY data sets with which we observe 92% and 88% of correlation on respectively the reconstructed Strehl Ratio (SR)/Full Width at Half Maximum (FWHM) compared to the sky values. The reference method achieves 95% and 92.5% exploiting directly the measurements of the residual phase from the Canary Truth Sensor (TS).

We derive a physical model of the on-axis PSF for a high contrast imaging system such as GPI or SPHERE. This model is based on a multi-spectral Taylor series expansion of the diffraction pattern and predicts that the speckles should be a combination of spatial modes with deterministic chromatic magnification and weighting. We propose to remove most of the residuals by fitting this model on a set of images at multiple wavelengths and times. On simulated data, we demonstrate that our approach achieves very good speckle suppression without additional heuristic parameters.

The residual speckles^{1, 2} set the most serious limitation in the detection of exo-planets in high contrast coronographic images provided by instruments such as SPHERE³ at the VLT, GPI^{4, 5} at Gemini, or SCExAO⁶ at Subaru. A number of post-processing methods have been proposed to remove as much as possible of the residual speckles while preserving the signal from the planets. These methods exploit the fact that the speckles and the planetary signal have different temporal and spectral behaviors. Some methods like LOCI⁷ are based on angular differential imaging⁸ (ADI), spectral differential imaging^{9, 10} (SDI), or on a combination of ADI and SDI.11 Instead of working on image differences, we propose to tackle the exo-planet detection as an inverse problem where a model of the residual speckles is fit on the set of multi-spectral images and, possibly, multiple exposures. In order to reduce the number of degrees of freedom, we impose specific constraints on the spatio-spectral distribution of stellar speckles. These constraints are deduced from a multi-spectral Taylor series expansion of the diffraction pattern for an on-axis source which implies that the speckles are a combination of spatial modes with deterministic chromatic magnification and weighting. Using simulated data, the efficiency of speckle removal by fitting the proposed multi-spectral model is compared to the result of using an approximation based on the singular value decomposition of the rescaled images. We show how the difficult problem to fitting a bilinear model on the can be solved in practise. The results are promising for further developments including application to real data and joint planet detection in multi-variate data (multi-spectral and multiple exposures images).

The advent of Wide Field Adaptive Optics (WFAO) systems marks the beginning of a new era in high spatial resolution imaging. The newly commissioned Gemini South Multi-Conjugate Adaptive Optics System (GeMS) combined with the infrared camera Gemini South Adaptive Optics Imager (GSAOI), delivers quasi diffraction-limited images over a field of ∼ 2 arc-minutes across. However, despite this excellent performance, some variable residues still limit the quality of the analyses. In particular, distortions severely affect GSAOI and become a critical issue for high-precision astrometry and photometry. In this paper, we investigate an optimal way to correct for the distortion following an inverse problem approach. Formalism as well as applications on GeMS data are presented.

The Giant Magellan Telescope (GMT) has a Gregorian 25.4-meter diameter primary mirror composed of seven 8.4-meter diameter segments. The secondary mirror consists of seven 1.1-meter diameter segments. In the active and adaptive operation modes of the GMT, around a dozen wavefront sensors are selectively used to monitor the optical aberrations across the focal plane. A dedicated wavefront control system drives slow and fast corrections at the M1 and M2 mirrors to deliver image quality optimized for the field of view of the scientific instrument in use. This paper describes the control strategies for the active optics mode of the GMT. Different wavefront estimation algorithm are compared and the performance of the GMT is evaluated using the Dynamic Optical Simulation package.

GALACSI is the Adaptive Optics (AO) system serving the instrument MUSE in the framework of the Adaptive Optics Facility (AOF) project. Its Narrow Field Mode (NFM) is a Laser Tomography AO (LTAO) mode delivering high resolution in the visible across a small Field of View (FoV) of 7.5" diameter around the optical axis. From a reconstruction standpoint, GALACSI NFM intends to optimize the correction on axis by estimating the turbulence in volume via a tomographic process, then projecting the turbulence profile onto one single Deformable Mirror (DM) located in the pupil, close to the ground.

In this paper, the laser tomographic reconstruction process is described. Several methods (virtual DM, virtual layer projection) are studied, under the constraint of a single matrix vector multiplication. The pseudo-synthetic interaction matrix model and the LTAO reconstructor design are analysed. Moreover, the reconstruction parameter space is explored, in particular the regularization terms.

Furthermore, we present here the strategy to define the modal control basis and split the reconstruction between the Low Order (LO) loop and the High Order (HO) loop. Finally, closed loop performance obtained with a 3D turbulence generator will be analysed with respect to the most relevant system parameters to be tuned.

NGS2 is an upgrade for the multi-natural guide star tip-tilt & plate scale wavefront sensor for GeMS (Gemini Multi-Conjugate Adaptive Optics system). It uses a single Nüvü HNü-512 Electron-Multiplied CCD array that spans the entire GeMS wavefront sensor focal plane. Multiple small regions-of-interest are used to enable frame rates up to 800Hz. This set up will improve the optical throughput with respect to the current wavefront sensor, as well as streamline acquisition and allow for distortion compensation.

Laser Guide Stars (LGS) have greatly increased the sky-coverage of Adaptive Optics (AO) systems. Due to the up-link turbulence experienced by LGSs, a Natural Guide Star (NGS) is still required, limiting sky-coverage. A method has recently been presented that promises to determine the LGS uplink tip-tilt in tomographic LGS AO systems by using the fact that each LGS Wave Front Sensor (WFS) in a tomographic AO system observes the uplink path of other LGSs. Such a technique has the potential to greatly increase the sky-coverage of Multi- Object, Laser Tomographic and Multi-Conjugate AO systems by allowed further off-axis NGS tip-tilt stars to be used for correction. Here we use an approach based on phase gradient covariance matrices to create on-sky capable tomographic reconstructors that account for some tip-tilt from LGS WFSs. We present analysis of open loop wave front sensor data from the CANARY Multi-Object AO demonstrator, providing early validation for the technique.

Measurement errors due to aliasing in a Shack-Hartmann WFS are typically 40% larger in variance than the fitting error of an AO system. On bright stars, aliasing is the dominant error within the control radius of the deformable mirror. Wavefront spatial frequencies beyond the WFS’ Nyquist frequency corrupt measurements below this frequency. A common misconception is to think that aliasing primarily affects the higher spatial frequency measurements. But in fact aliasing propagates to the lowest order modes, and corrupts even tip/tilt. There are many examples including the observation that the temporal power spectrum of measured tip/tilt from a WFS does not correspond to Kolmogorov theory. We propose a simple optical modification to a SH WFS (borrowed from the digital video camera industry), and present simulation results showing that the aliasing errors are reduced.

Small inner working angle coronagraphs are essential to benefit from the full potential of large and future extremely large ground-based telescopes, especially in the context of the detection and characterization of exoplanets. Among existing solutions, the vortex coronagraph stands as one of the most effective and promising solutions. However, for focal-plane coronagraph, a small inner working angle comes necessarily at the cost of a high sensitivity to pointing errors. This is the reason why a pointing control system is imperative to stabilize the star on the vortex center against pointing drifts due to mechanical flexures, that generally occur during observation due for instance to temperature and/or gravity variations. We have therefore developed a technique called QACITS¹ (Quadrant Analysis of Coronagraphic Images for Tip-tilt Sensing), which is based on the analysis of the coronagraphic image shape to infer the amount of pointing error. It has been shown that the flux gradient in the image is directly related to the amount of tip-tilt affecting the beam. The main advantage of this technique is that it does not require any additional setup and can thus be easily implemented on all current facilities equipped with a vortex phase mask. In this paper, we focus on the implementation of the QACITS sensor at Keck/NIRC2, where an L-band AGPM has been recently commissioned (June and October 2015), successfully validating the QACITS estimator in the case of a centrally obstructed pupil. The algorithm has been designed to be easily handled by any user observing in vortex mode, which is available for science in shared risk mode since 2016B.

Non-Common Path Errors (NCPEs) are the dominant factor limiting the performance of current astronomical high-contrast imaging instruments. If uncorrected, the resulting quasi-static speckle noise floor limits coronagraph performance to a raw contrast of typically 10⁻⁴, a value which does not improve with increasing integration time. The coronagraphic Modal Wavefront Sensor (cMWS) is a hybrid phase optic which uses holographic PSF copies to supply focal-plane wavefront sensing information directly from the science camera, whilst maintaining a bias-free coronagraphic PSF. This concept has already been successfully implemented on-sky at the William Herschel Telescope (WHT), La Palma, demonstrating both real-time wavefront sensing capability and successful extraction of slowly varying wavefront errors under a dominant and rapidly changing atmospheric speckle foreground. In this work we present an overview of the development of the cMWS and recent first light results obtained using the Leiden EXoplanet Instrument (LEXI), a high-contrast imager and high-dispersion spectrograph pathfinder instrument for the WHT.

On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph operates in the L' band not only in order to take advantage from the favorable star/planet contrast ratio when observing beyond the K band, but also to exploit the fact that the Keck II Adaptive Optics (AO) system delivers nearly extreme adaptive optics image quality (Strehl ratios values near 90%) at 3.7μm. We describe the hardware installation of the vortex phase mask during a routine NIRC2 service mission. The success of the project depends on extensive software development which has allowed the achievement of exquisite real-time pointing control as well as further contrast improvements by using speckle nulling to mitigate the effect of static speckles. First light of the new coronagraphic mode was on June 2015 with already very good initial results. Subsequent commissioning nights were interlaced with science nights by members of the VORTEX team with their respective scientific programs. The new capability and excellent results so far have motivated the VORTEX team and the Keck Science Steering Committee (KSSC) to offer the new mode in shared risk mode for 2016B.

We present the properties of the adaptive optics (AO) system of the German 1.5m solar telescope GREGOR, located on the island of Tenerife, Spain. The conventional AO system uses a correlating Shack-Hartmann-Sensor with a 92mm subaperture size and a 256-actuator stacked-piezo deformable mirror (DM). AO performance results and practical experience based on the last four years of operation are presented. A recently installed second wavefront sensor with exchangeable lenslets / subaperture sizes in combination with an EM-CCD camera is used for low light observations such as polarimetric measurements of the solar system planets. Further developments include algorithmic improvements, the use of the night-time sensor for solar (off-limb) observations and solar MCAO.

The sky coverage and performance of Laser Guide Star (LGS) adaptive optics (AO) systems is limited by the Natural Guide Star (NGS) used for low order correction (tip-tilt and defocus modes). This limitation can be reduced by measuring image motion of the NGS in the near-infrared where it is partially corrected by the LGS AO system and where stars are generally several magnitudes brighter than at visible wavelengths. We have integrated a Near-InfraRed Tip-Tilt Sensor (NIRTTS) with the Keck I telescopes LGS AO system. The sensor is a H2RG-based near-infrared camera with 0.05 arcsecond pixels. Low noise at high sample rates is achieved by only reading a small region of interest, from 2x2 to 16x16 pixels, centered on an NGS anywhere in an 100 arc second diameter field. The sensor operates at either Ks or H-band using light reflected by a choice of dichroic beam-splitters located in front of the OSIRIS integral field spectrograph. The implementation of the NIRTTS involved modifications to the AO bench, real-time control system, higher-level controls and operations software. NIRTTS is nearly ready for science operation in shared-risk mode. We are also implementing a number of enhancements to the NIRTTS system which involve substantial changes to the operations software. This work presents an update of the work performed since the NIRTTS system was reported in Ref. 1 and Ref. 2.

SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) is a second generation VLT instrument aimed at the direct detection of exo-planets. It has received its first light in May 2014. ZIMPOL (Zurich Imaging Polarimeter) is the imaging polarimeter subsystem of the SPHERE instrument. It's capable of both high accuracy and high sensitivity polarimetry but can also be used as a classical imager. It is located behind an extreme AO system and a stellar coronagraph. ZIMPOL operates at visible wavelengths which is best suited to detect the very faint reflected and hence polarized visible light from extra solar planets. During the SPHERE fourth commissioning period (October 2014) we have made deep coronagraphic observations of the bright star alpha Gru (mR = 1.75) to assess the high contrast polarimetric performance of SPHERE-ZIMPOL. We have integrated on the target for a total time of about 45 minutes during the meridian transit in the Very Broad Band filter (600 - 900 nm) with a classical Lyot coronagraph with 3 λ/D radius focal mask. We reduce the data by a combination of Polarized Background subtraction, Polarimetric Differential Imaging (PDI) and Angular Differential Imaging (ADI). We reach contrasts of 10-6 and 10-7 at a radial distances of respectively 7 and 14 lambda/D from the PSF core. At these radial distances we are respectively a factor of 10 and 2 above the photon noise limit. We discuss our results by considering the temporal and spatial speckle behavior close to the PSF core in combination with low order polarimetric aberrations.

The multi-conjugate adaptive optics (MCAO) system for solar observations at the 1.6-meter clear aperture New Solar Telescope (NST) of the Big Bear Solar Observatory (BBSO) in Big Bear Lake, California, enables us to study fundamental design questions in solar MCAO experimentally. It is the pathfinder for MCAO of the upcoming Daniel K. Inoyue Solar Telescope (DKIST). This system is very flexible and offers various optical configurations such as different sequencings of deformable mirrors (DMs) and wavefront sensors (WFS), which are hard to simulate conclusively. We show preliminary results and summarize the design, and 2016 updates to the MCAO system. The system utilizes three DMs. One of which is conjugate to the telescope pupil, and the other two to distinct higher altitudes. The pupil DM can be either placed into a pupil image up- or downstream of the high-altitude DMs. The high-altitude DMs can be separately and quickly conjugated to various altitudes between 2 and 8 km. Three Shack-Hartmann WFS units are available, one for low-order, multi-directional sensing and two high-order on-axis sensing.

Solar observation with high resolution in large field of view (FoV) is required for some solar active regions with the typical sizes of 1’ to 3’. Conventional adaptive optics (AO) could not satisfy this demand because of the atmospheric anisoplanatism. Through compensating the turbulence in different heights, multi-conjugate adaptive optics (MCAO) has been proved to obtain a larger corrected FoV. A MCAO experimental system including a conventional 151-element AO system and a 37-element MCAO part is being developed. The MCAO part contains a 37-element deformable mirror conjugated into the 2km to 5km height and a multi-direction Shack-Hartmann wavefront sensor (MD-SHWFS) with 7×7 subaperture array and 60 arcsec FoV, the frame rate of the MD-SHWFS is up to 840Hz. Three-dimensional (3-D) wavefront sensing utilizing atmospheric tomography had been validated by solar observation. Based on these results, a ground layer adaptive optics (GLAO) experimental system including a 151-element deformable mirror and the MD-SHWFS has been built at the 1m New Vacuum Solar Telescope (NVST). In this paper, the MCAO experimental system will be introduced. The preliminary experimental results of three-dimensional wavefront sensing and GLAO on the NVST of Full-shine Lake Solar Observatory are presented.

MAORY is one of the four instruments for the E-ELT approved for construction. It is an adaptive optics module offering two compensation modes: multi-conjugate and single-conjugate adaptive optics. The project has recently entered its phase B. A system-level overview of the current status of the project is given in this paper.

We present an overview of the current and future adaptive optics systems at the LBTO along with the current and planned science instruments they feed. All the AO systems make use of the two 672 actuator adaptive secondary mirrors. They are (1) FLAO (NGS/SCAO) feeding the LUCI NIR imagers/spectrographs; (2) LBTI/AO (NGS/SCAO) feeding the NIR/MIR imagers and LBTI beam combiner; (3) the ARGOS LGS GLAO system feeding LUCIs; and (4) LINC-NIRVANA - an NGS/MCAO imager and interferometer system. AO performance of the current systems is presented along with proposed performances for the newer systems taking into account the future instrumentation.

GeMS, the Gemini South MCAO System, has now been in operation for 3 years with the near infrared imager GSAOI. We first review the performance obtained by the system, the science cases and the current operational model. In the very near future, GeMS will undergo a profound metamorphosis, as we will integrate a new NGS wavefront sensor, replace the current 50W laser with a more robust one and prepare for a new operational model where operations will shift from the mountain to the base facility. Along this major evolution, we are also presenting several improvements on the loop control, calibrations and automatization of this complex system. We discuss here the progress of the different upgrades and what we expect in terms of performance improvements and operational efficiency.

The goal for the adaptive optics systems at the Large Binocular Telescope Observatory (LBTO) is for them to operate fully automatically, without the need for an AO Scientist, and to be run by the observers and/or the telescope operator. This has been built into their design. Initially, the AO systems would close the loop using optimal parameters based on the observing conditions and guide star brightness, without adapting to changing conditions. We present the current status of AO operations as well as recent updates that improve the operational efficiency and minimize downtime. Onsky efficiency and performance will also be presented, along with calibrations required for AO closed loop operation.

GRAAL is the adaptive optics module feeding the wide-field IR imager HAWK-I at the VLT observatory. As part of the adaptive optics facility, GRAAL is equipped with 4 Laser-guide star wave-front sensors and provides a large field-of-view, ground layer correction system to HAWK-I. After a successful testing in Europe, the module has been re-assembled in Chile and installed at the Nasmyth-A platform of Yepun, the fourth Unit telescope of the observatory. We report on the installation of GRAAL on the mountain and on its first testing in stand-alone and on-sky.

Adaptive Optics (AO) has become the requisite equipment of the ground-based large solar telescope to correct the wavefront aberration induced by the atmospheric turbulence. Two generation solar AO systems, one is the 37-element loworder AO system with 2100Hz frame rate and the other is 151-element high-order AO system with 3500Hz frame rate, were successfully developed in 2013 and 2015 respectively. In this presentation, the development of the two AO systems for 1-m New Vacuum Solar Telescope (NVST) at Fuxian Solar Observatory (FSO) will be introduced and the solar high resolution observational results are presented.

The present work is an attempt to characterize the performances of SINFONI, how we follow the history line of its key parameters and detect possible problems. We will make a review of the health check, with analysis of the long term trends. We will analyze the transfer function of the system during the calibrations and on sky, and evaluate their sensitivity and relation to external parameters. The study of the trends of the key parameters of the instrument provides useful analysis and monitoring to determine when an instrument eventually starts to degrade or to trace in time the different events in its maintenance. One can also determine when a major intervention or upgrade of the system might be necessary, where to focus the efforts to maximize the gain versus the work performed, and provides useful information on the status of the instrument prior to the intervention.

GRAVITY is a second generation near-infrared VLTI instrument that will combine the light of the four unit or four auxiliary telescopes of the ESO Paranal observatory in Chile. The major science goals are the observation of objects in close orbit around, or spiraling into the black hole in the Galactic center with unrivaled sensitivity and angular resolution as well as studies of young stellar objects and evolved stars. In order to cancel out the effect of atmospheric turbulence and to be able to see beyond dusty layers, it needs infrared wave-front sensors when operating with the unit telescopes. Therefore GRAVITY consists of the Beam Combiner Instrument (BCI) located in the VLTI laboratory and a wave-front sensor in each unit telescope Coudé room, thus aptly named Coudé Infrared Adaptive Optics (CIAO). This paper describes the CIAO design, assembly, integration and verification at the Paranal observatory.

GRAVITY is a near-infrared interferometric instrument that allows astronomers to combine the light of the four unit or four auxiliary telescopes of the ESO Very Large Telescope in Paranal, Chile. GRAVITY will deliver extremely precise relative astrometry and spatially resolved spectra. In order to study objects in regions of high extinction (e.g. the Galactic Center, or star forming regions), GRAVITY will use infrared wavefront sensors. The suite of four wavefront sensors located in the Coudé room of each of the unit telescopes are known as the Coudé Integrated Adaptive Optics (CIAO). The CIAO wavefront sensors are being constructed by the Max Planck Institute for Astronomy (MPIA) and are being installed and commissioned at Paranal between February and September of 2016. This presentation will focus on system tests performed in the MPIA adaptive optics laboratory in Heidelberg, Germany in preparation for shipment to Paranal, as well as on-sky data from the commissioning of the first instrument. We will discuss the CIAO instruments, control strategy, optimizations, and performance at the telescope.

An adaptive optics (AO) system is developed for the 60cm domeless solar telescope of the Hida Observatory, Japan. Its performances are analyzed by the computer simulations, and improved by replacing the Zernike polynomials by Karhunen-Loève functions. Also, a tomographic wavefront sensor is developed for a ground-layer AO system. From test data acquired at the Hida observatory, wavefront-phase maps both in the ground-layer and in an upper layer are successfully derived.

For two years starting in February 2014, the AO modules GRAAL for HAWK-I and GALACSI for MUSE of the Adaptive Optics Facility project have undergone System Testing at ESO's Headquarters. They offer four different modes: NGS SCAO, LGS GLAO in the IR, LGS GLAO and LTAO in the visible. A detailed characterization of those modes was made possible by the existence of ASSIST, a test bench emulating an adaptive VLT including the Deformable Secondary Mirror, a star simulator and turbulence generator and a VLT focal plane re-imager. This phase aimed at validating all the possible components and loops of the AO modules before installation at the actual VLT that comprises the added complexity of real LGSs, a harsher non-reproducible environment and the adaptive telescope control.

In this paper we present some of the major results obtained and challenges encountered during the phase of System Tests, like the preparation of the Acquisition sequence, the testing of the Jitter loop, the performance optimization in GLAO and the offload of low-order modes from the DSM to the telescope (restricted to the M2 hexapod). The System Tests concluded with the successful acceptance, shipping, installation and first commissioning of GRAAL in 2015 as well as the acceptance and shipping of GALACSI, ready for installation and commissioning early 2017.

More than 10 years have already passed since the first Multiple Application Curvature Adaptive Optics (MACAO) facilities got the first light in UT2 the 18^th of April, 2003, in the Very Large Telescope (VLT) at Paranal Observatory.

The achievable image sharpness of a ground-based telescope is normally limited by the effect of atmospheric turbulence. However, with Adaptive Optics (AO) techniques, this major drawback can be overcome so that the telescope produces images that are as sharp as theoretically possible, i.e., as if they were taken from space. [1]

The intention of this document is summarize in few pages some highlights related with the activities needed to keep MACAO units in operation. Some statistics of problems based in Action Remedy tool is included, showing how through these years the number of problems has been reduced, even when there are still some unsolved ones. Some lessons have been learned and there are others one to learn. Corrective and predictive maintenance performed are shown too like the current measurements, transfer functions measurements, thermography pictures, health checks measuring interaction matrix and flat vectors to detect dead APDs or short circuits in the DM, etc. Some forced interventions are included as well like the removal of the cabinets from Coude rooms to avoid that acoustic noise and vibrations perturb the operations, the deformable mirrors reached by cooling leaks and a mirror that got rusty are shown too.

Well knowledge of the system, good interaction between different disciplines groups to perform corrective and preventive maintenance seems to be key aspects of keeping it under control and operative during all these years leading to this good result.

LINC-NIRVANA is an innovative, high-resolution, near-infrared imager for the Large Binocular Telescope. Its Multi-Conjugate Adaptive Optics system uses natural guide-stars and the layer-oriented, multiple-field of view approach for high sky coverage and eventual interferometric beam combination. We describe LINC-NIRVANA’s particular flavour of MCAO and its associated challenges, and report on final lab integration and system level testing. LINC-NIRVANA is currently at the telescope undergoing final alignment and tests before First Light late this fall.

With the upcoming construction of ELTs, several existing technologies are being pushed beyond their performance limit and it became essential to develop and evaluate alternatives. We present a specifically designed focal plane box which will allow to evaluate, directly on-sky, the performance of a number of next generation adaptive optics related technologies The system will able us to compare the performance of several new wavefront sensors in contrast to a Shack-Hartman wavefront sensor. The system has been designed for the "Observatoire du Mont Mégantic" (OMM) which hosts a telescope having a 1.6-meter diameter primary. The OMM telescope, located halfway between Montreal and Quebec City, is known to be an excellent location to develop and test precursor instruments which can then be upscaled to larger telescopes (ex. SPIOMM which led to SITELLE at the CFHT). We present the results of the first run made at the telescope and also identify problems that were encountered. We also propose a series of modifications to the system that will help to solve these issues.

We present a review of the ongoing research activity surrounding the adaptive optics system at the Shane telescope (ShaneAO) particularly the R&D efforts on the technology and algorithms for that will advance AO into wider application for astronomy. We are pursuing the AO challenges for whole sky coverage diffraction-limited correction down to visible science wavelengths. This demands high-order wavefront correction and bright artificial laser beacons. We present recent advancements in the development of MEMS based AO correction, woofer-tweeter architecture, wind-predictive wavefront control algorithms, atmospheric characterization, and a pulsed fiber amplifier guide star laser tuned for optical pumping of the sodium layer. We present the latest on-sky results from the new AO system and present status and experimental plans for the optical pumping guide star laser.

The demonstration of efficient single-mode fiber (SMF) coupling is a key requirement for the development of a compact, ultra-precise radial velocity (RV) spectrograph. iLocater is a next generation instrument for the Large Binocular Telescope (LBT) that uses adaptive optics (AO) to inject starlight into a SMF. In preparation for commissioning iLocater, a prototype SMF injection system was installed and tested at the LBT in the Y-band (0.970–1.065 μm). This system was designed to verify the capability of the LBT AO system as well as characterize on-sky SMF coupling efficiencies. SMF coupling was measured on stars with variable airmasses, apparent magnitudes, and seeing conditions for six half-nights using the Large Binocular Telescope Interferometer. We present the overall optical and mechanical performance of the SMF injection system, including details of the installation and alignment procedure. A particular emphasis is placed on analyzing the instrument's performance as a function of telescope elevation to inform the final design of the fiber injection system for iLocater.

The MACAO curvature wavefront sensors have been designed as a generic adaptive optics sensor for the Very Large Telescope. Six systems have been manufactured and implemented on sky: four installed in the UTs Coudé train as an AO facility for the VLTI, and two in UT’s instruments, SINFONI and CRIRES. The MACAO-VLTI have now been in use for scientific operation for more than a decade and are planned to be operated for at least ten more years. As second generation instruments for the VLTI were planned to start implementation in end of 2015, accompanied with a major upgrade of the VLTI infrastructure, we saw it as a good time for a rejuvenation project of these systems, correcting the obsolete components. This obsolescence correction also gave us the opportunity to implement improved capabilities: the correction frequency was pushed from 420 Hz to 1050 Hz, and an automatic vibrations compensation algorithm was added. The implementation on the first MACAO was done in October 2014 and the first phase of obsolescence correction was completed in all four MACAO-VLTI systems in October 2015 with the systems delivered back to operation. The resuming of the scientific operation of the VLTI on the UTs in November 2015 allowed to gather statistics in order to evaluate the improvement of the performances through this upgrade. A second phase of obsolescence correction has now been started, together with a global reflection on possible further improvements to secure observations with the VLTI.

GALACSI is the Adaptive Optics (AO) module that will serve the MUSE Integral Field Spectrograph. In Wide Field Mode it will enhance the collected energy in a 0.2”×0.2” pixel by a factor 2 at 750 nm over a Field of View (FoV) of 1’×1’ using the Ground Layer AO (GLAO) technique. In Narrow Field Mode, it will provide a Strehl Ratio of 5% (goal 10%) at 650 nm, but in a smaller FoV (7.5”×7.5” FoV), using Laser Tomography AO (LTAO). Before being ready for shipping to Paranal, the system has gone through an extensive testing phase in Europe, first in standalone mode and then in closed loop with the DSM in Europe. After outlining the technical features of the system, we describe here the first part of that testing phase and the integration with the AOF ASSIST (Adaptive Secondary Setup and Instrument Stimulator) testbench, including a specific adapter for the IRLOS truth sensor. The procedures for the standalone verification of the main system performances are outlined, and the results of the internal functional tests of GALACSI after full integration and alignment on ASSIST are presented.

The CANARY-Hosted Upgrade for High-Order Adaptive Optics (CHOUGH), is a narrow-field of view High- Order Single Conjugate on-sky AO demonstrator to be placed on the 4.2m WHT telescope. It aims to produce a Strehl ratio greater than 0.5 in the visible region of the spectrum (> 640nm). A High-Order wave-front sensor (HOWFS) is a central piece of the experiment; it is a Shack-Hartmann with a sampling of 31x31 subapertures across the pupil. A variable aperture spatial filter designed to reduce aliasing for high-spatial frequencies, located at a focal plane preceding the lenslet array. The HOWFS has a quad-cell configuration on the detector with a one-pixel guard ring and 48μm subaperture. The detector is a NuVu EMCCD camera, 24μm pixel size, operating at >500Hz. The lenslet array, collimator and relay are commercial off-the-shelf. This was technically challenging due to the small size of the pupil, 2.3mm, and the small optics involved in the design.

SHARK-NIR channel is one of the two coronagraphic instruments proposed for the Large Binocular Telescope, in the framework of the call for second generation instruments, issued in 2014. Together with the SHARK-VIS channel, it will offer a few observing modes (direct imaging, coronagraphic imaging and coronagraphic low resolution spectroscopy) covering a wide wavelength domain, going from 0.5μm to 1.7μm.

Initially proposed as an instrument covering also the K-band, the current design foresees a camera working from Y to H bands, exploiting in this way the synergy with other LBT instruments such as LBTI, which is actually covering wavelengths greater than L' band, and it will be soon upgraded to work also in K band. SHARK-NIR has been undergoing the conceptual design review at the end of 2015 and it has been approved to proceed to the final design phase, receiving the green light for successive construction and installation at LBT.

The current design is significantly more flexible than the previous one, having an additional intermediate pupil plane that will allow the usage of coronagraphic techniques very efficient in term of contrast and vicinity to the star, increasing the instrument coronagraphic performance. The latter is necessary to properly exploit the search of giant exo-planets, which is the main science case and the driver for the technical choices of SHARK-NIR. We also emphasize that the LBT AO SOUL upgrade will further improve the AO performance, making possible to extend the exo-planet search to target fainter than normally achieved by other 8-m class telescopes, and opening in this way to other very interesting scientific scenarios, such as the characterization of AGN and Quasars (normally too faint to be observed) and increasing considerably the sample of disks and jets to be studied.

Finally, we emphasize that SHARK-NIR will offer XAO direct imaging capability on a FoV of about 15"x15", and a simple coronagraphic spectroscopic mode offering spectral resolution ranging from few hundreds to few thousands. This article presents the current instrument design, together with the milestones for its installation at LBT.

In this article, we describe the development of the newest adaptive optics system for the Big Solar Vacuum Telescope of the Baikal Astrophysical Observatory. This system is a result of collaboration between VE Zuev Institute of Atmospheric Optics SB RAS, Tomsk, and Institute of Solar-Terrestrial Physics SB RAS, Irkutsk. The system includes two active mirrors for the correction: domestic tip-tilt and bimorph deformable (Active Optics NightN Ltd.), and separate wavefront sensors (WFS). A correlation S-H wave-front sensor is based on a Allies Prosilica GX-1050 GigE camera with speed of 309 Hz and frame size of 1248x1248 pixels. A personal computer is used for bimorph deformable mirror image processing. The mirror was successfully used during the 2010–2014 observing seasons. The system developed is capable of correcting up to 35 modes, thus providing diffraction limited images at visible wavelengths.

The Australian Astronomical Observatory is currently investigating the use of adaptive optics technologies for the 3.9m Anglo-Australian Telescope at Siding Spring Observatory. It might be that ground-layer or multi-object adaptive optics is beneficial for the Anglo-Australian Telescope (seeing ∼1.5"). Key to achieving this goal is an adaptive optics test-bench developed for laboratory experiments and on-sky demonstration. The test-bench provides a facility to demonstrate on-sky natural guide star adaptive optics as well as second stage correction with active injection into single mode waveguides. The test-bench provides wide field access of up to 20 arcminutes for testing our plug-plate distributed wavefront sensors. Data has been collected in a range of seeing conditions where closed-loop corrections were performed. We present the design, results and plans for the adaptive optics on-sky demonstrator.

The Narrow Field InfraRed Adaptive Optics System (NFIRAOS) will be the first-light facility Adaptive Optics (AO) system for the Thirty Meter Telescope (TMT). NFIRAOS will be able to host three science instruments that can take advantage of this high performance system. NRC Herzberg is leading the design effort for this critical TMT subsystem. As part of the final design phase of NFIRAOS, we have identified multiple subsystems to be sub-contracted to Canadian industry. The scope of work for each subcontract is guided by the NFIRAOS Work Breakdown Structure (WBS) and is divided into two phases: the completion of the final design and the fabrication, assembly and delivery of the final product. Integration of the subsystems at NRC will require a detailed understanding of the interfaces between the subsystems, and this work has begun by defining the interface physical characteristics, stability, local coordinate systems, and alignment features. In order to maintain our stringent performance requirements, the interface parameters for each subsystem are captured in multiple performance budgets, which allow a bottom-up error estimate. In this paper we discuss our approach for defining the interfaces in a consistent manner and present an example error budget that is influenced by multiple subsystems.

The Adaptive optics for GTC is a single conjugated post focal AO system placed in the Nasmyth platform over a static optical table. It has been designed initially for natural guide star and in the later project phase adapted to one laser guide star. The AO system is composed of the following subsystems: wavefront corrector, wavefront sensor, structure, calibration system and test camera. This paper presents the hardware electronics to support all these subsystems including a real time control introduction.

One year and an half after ARGOS first light, the Large Binocular Telescope (LBT) laser guided ground-layer adaptive optics (GLAO) system has been operated on both sides of the LBT. The system fulfills the GLAO promise and typically delivers an improvement by a factor of 2 in FWHM over the 4'×4' field of view of both Luci instruments, the two near-infrared imagers and multi-object spectrographs.

In this paper, we report on the first on-sky results and analyze the performances based on the data collected so far. We also discuss adaptive optics procedures and the joint operations with Luci for science observations.

Paranal Observatory has a set of astroclimate monitoring instruments; such as DIMM, MASS-DIMM and SLODAR which are delivering information about the sky quality in terms of; seeing, coherence time, high altitude wind speed (200mb) and C_n² profiles to support the observations. SPHERE instrument is an Extreme Adaptive Optics that uses a Shack-Hartmann wavefront sensor running at close loop frequency of 1.3KHz. The instrument saves close loop snapshot every minute and from the data saved the system retrieves the r0 and the cross wind speed. The wind speed is calculated using a cross-corrrelation based on the peak identification. The knowledge of t his parameter is essential to understand the performances of the AO system, and to optimize its control laws every minutes. The data from the astroclimatic system monitor will help to correlate the turbulence events with the transverse wind speed retrieved from SPHERE close loop data. The goal of this work is also to compare the different atmospheric monitors with the effective turbulence estimation from the focal plane itself (Differential Tip-Tilt Sensor).

In this paper we study the abilities of an atmospherical mesoscale model in forecasting the classical atmospherical parameters relevant for astronomical applications at the surface layer (wind speed, wind direction, temperature, relative humidity) on the Large Binocular Telescope (LBT) site - Mount Graham, Arizona. The study is carried out in the framework of the ALTA project aiming at implementing an automated system for the forecasts of atmospherical parameters (Meso-Nh code) and the optical turbulence (Astro-Meso-Nh code) for the service-mode operation of the LBT. The final goal of such an operational tool is to provide predictions with high time frequency of atmospheric and optical parameters for an optimized planning of the telescope operation (dome thermalization, wind-dependent dome orientation, observation planning based on predicted seeing, adaptive optics optimization, etc...). Numerical simulations are carried out with the Meso-Nh and Astro-Meso-Nh codes, which were proven to give excellent results in previous studies focused on the two ESO sites of Cerro Paranal and Cerro Armazones (MOSE Project). In this paper we will focus our attention on the comparison of atmospherical parameters forescasted by the model close to the ground with measurements taken by the observatory instrumentations and stored in the LBT telemetry in order to validate the numerical predictions. As previously done for Cerro Paranal (Lascaux et al., 2015), we will also present an analysis of the model performances based on the method of the contingency tables, that allows us to provide complementary key information with the respect to the bias and RMSE (systematic and statistical errors), such as the percentage of correct detection and the probability to obtain a correct detection inside a defined interval of values.

Wide Field Adaptive Optics (WFAO) systems represent the more sophisticated AO systems available today at large telescopes. One critical aspect for these WFAO systems in order to deliver an optimised performance is the knowledge of the vertical spatiotemporal distribution of the C_N² and the wind speed. Previous studies (Cortes et al., 2012[¹]) already proved the ability of GeMS (the Gemini Multi-Conjugated AO system) in retrieving C_N² and wind vertical stratification using the telemetry data. To assess the reliability of the GeMS wind speed estimates a preliminary study (Neichel et al., 2014[²]) compared wind speed retrieved from GeMS with that obtained with the atmospherical model Meso-Nh on a small sample of nights providing promising results. The latter technique is very reliable for the wind speed vertical stratification. The model outputs gave, indeed, an excellent agreement with a large sample of radiosoundings (∼ 50) both in statistical terms and on individual flights (Masciadri et al., 2013[³]). Such a tool can therefore be used as a valuable reference in this exercise of cross calibrating GeMS on-sky wind estimates with model predictions. The main results of Neichel et al. (2014) analysis showed that, on a great number of cases, GeMS could reconstruct very good wind speed estimates. At the same time it has been put in evidence, on a number of cases, not negligible discrepancies from the atmospherical model. However we observed that these discrepancies strongly decreased or even disappear if GeMS data reduction is done with the a priori knowledge of the wind speed stratification provided by the model Meso-Nh. Basically the a priori knowledge helped the data reduction of GeMS acquisitions. In this contribution we achieved a two-fold results: (1) we extended analysis on a much richer statistical sample (∼ 43 nights), we confirmed the preliminary results and we found an even better correlation between GeMS observations and the atmospherical model with basically no cases of not-negligible uncertainties; (2) we evaluate the possibility to use, as an input for GeMS, the Meso-Nh estimates of the wind speed stratification in an operational configuration. Under this configuration these estimates can be provided many hours in advanced with respect to the observations and with a very high temporal frequency (order of 2 minutes or less). Such a system would have a set of advantages: (a) to implement inside GeMS a total temporal and spatial coverage of the wind speed over ∼ 20 km and all along the night not only in real-time but in advance of a few hours, (b) to improve the detection of the C_N² vertical stratification from GeMS because a good wind speed estimation would improve the quality of the cross-correlation peaks detection, (c) the possibility to bypass the complex (and not necessarily reliable) procedures necessary to automatise the wind speed estimate of GeMS due to the relatively low vertical resolution of the system. Such a study can obviously be considered as a demonstrator for multiple operational AO and WFAO systems (AOF, LINC-NIRVANA, RAVEN, ...) of present top-class telescopes and for the forthcoming generation. It might have, therefore, an interest for the AO community well beyond the improvement of GeMS performance.

Estimating the outer scale profile, L₀(h) in the context of current very large and future extremely large telescopes is crucial, as it impacts the on-line estimation of turbulence parameters (Cn²(h), r₀, θ₀ and τ₀) and the performance of Wide Field Adaptive Optics (WFAO) systems. We describe an on-line technique that estimates L₀(h) using AO loop data available at the facility instruments. It constructs the cross-correlation functions of the slopes of two or more wavefront sensors, which are fitted to linear combinations of theoretical responses for individual layers with different altitudes and outer scale values.

We analyze some restrictions found in the estimation process, which are general to any measurement technique. The insensitivity of the instrument to large values of outer scale is one of them, as the telescope becomes blind to outer scales larger than its diameter. Another problem is the contradiction between the length of data and the stationarity assumption of the turbulence (turbulence parameters may change during the data acquisition time).

Our method effectively deals with problems such as noise estimation, asymmetric correlation functions and wavefront propagation effects. It is shown that the latter cannot be neglected in high resolution AO systems or strong turbulence at high altitudes. The method is applied to the Gemini South MCAO system (GeMS) that comprises five wavefront sensors and two DMs. Statistical values of L₀(h) at Cerro Pachón from data acquired with GeMS during three years are shown, where some interesting resemblance to other independent results in the literature are shown.

Satellite tracking and imaging is conducted by the ANU Research School of Astronomy and Astrophysics and Electro-Optic Systems (EOS) at Mount Stromlo Observatory, Canberra, Australia, as part of the Space Environment Management Cooperative Research Centre (SERC) to support the development in space situational awareness. Atmospheric turbulence leads to distortions in the measured data. Adaptive optics (AO) systems counteract those distortions and improve the resolution of the tracking and imaging systems. To assist in the design of the AO systems, we need to gather information on the atmosphere at Mount Stromlo: r₀, τ ₀, and the turbulence C_n² profile. With the SCIntillation Detection And Ranging (SCIDAR) Technique the scintillation of two stars is measured and their autocorrelation function is computed, providing a measurement of the turbulence profile. This technique usually uses one detector recording the two images of the stars simultaneously. However, the images overlap leading to an underestimation of the C_n² values. The introduction of stereo-SCIDAR1 over- comes this issue by separating the two stars and imaging them on two separate image sensors. To reduce costs, we introduce a new stereo-SCIDAR system separating the beams from the two stars, but using only one single detector. This has been shown for a Low Layer SCIDAR (LOLAS) system with wide double stars (200 arcsec). We investigate this technique by detecting the scintillation patterns of double stars with separation from 10 to 25 arcsec, allowing some flexibility in the altitude span and resolution, while retaining a simple optical setup. We selected a low noise sCMOS camera as the imager. We show the current design of this system and investigate its feasibility for further development.

Prior statistical knowledge of the turbulence such as turbulence strength, layer altitudes and the outer scale is essential for atmospheric tomography in adaptive-optics (AO). These atmospheric parameters can be estimated from measurements of multiple Shack-Hartmann wave-front sensors (SH-WFSs) by the SLOpe Detection And Ranging (SLODAR). In this paper, we present the statistics of the vertical C_N² and the outer scale L₀ at Maunakea in Hawaii estimated from 60 hours telemetry data in total from multiple SH-WFSs of RAVEN, which is an on-sky multi-object AO demonstrator tested on the Subaru telescope. The mean seeing during the RAVEN on-sky observations is 0.475 arcsec, and 55% turbulence is below 1.5 km. The vertical profile of C_N² from the RAVEN SLODAR is consistent with the profiles from CFHT DIMM and MASS, and TMT site characterization.

Future high-contrast imagers on ground-based extremely large telescopes will have to deal with the segmentation of the primary mirrors. Residual phase errors coming from the phase steps at the edges of the segments will have to be minimized in order to reach the highest possible wavefront correction and thus the best contrast performance. To study these effects, we have developed the MITHIC high-contrast testbed, which is designed to test various strategies for wavefront sensing, including the Zernike sensor for Extremely accurate measurements of Low-level Differential Aberrations (ZELDA) and COronagraphic Focal-plane wave-Front Estimation for Exoplanet detection (COFFEE). We recently equipped the bench with a new atmospheric turbulence simulation module that offers both static phase patterns representing segmented primary mirrors and continuous phase strips representing atmospheric turbulence filtered by an AO or an XAO system. We present a characterisation of the module using different instruments and wavefront sensors, and the first coronagraphic measurements obtained on MITHIC.

The Magellan Telescope Adaptive Optics System (MagAO) is subject to resonance effects induced by elements within the system instrumentation, such as fans and cooling pumps. Normalized PSDs are obtained through frequency-based analysis of closed-loop on-sky data, detecting and measuring vibration effects. Subsequently, a space-state model for the AO loop is obtained, using a standard AO loop scheme with an integrator-based controller and including the vibration effects as disturbances. Finally, a new control alternative is proposed, focusing on residual phase variance minimization through the design and simulation of an optimal LQG control approach.

The local turbulence is the only part of the seeing degradation that we can actively improve and reduce at the source. It is often a major contribution to the overall seeing^1,2 and introduces effects that are highly localized and may be difficult to correct. For example, dome seeing is expected to be non-Kolmogorov, with a very small outer scale leading to a preponderance of high spatial frequencies. The first step in controlling the local seeing is to locate and quantify the turbulence present. This requires the development of a new type of sensor, specifically designed to sensitively measure local optical turbulence. We are in the process of developing such a sensor, based on a simple Mach-Zehnder interferometer layout. The sensor will be light and ruggedized so that it can be used to map out the turbulence inside the dome of any telescope, inside the telescope tube and even around the dome building. Eventually, such a sensor may be used to quantitatively and actively control dome vents.

To approach optimal performance advanced Adaptive Optics (AO) systems deployed on ground-based telescopes must have accurate knowledge of atmospheric turbulence as a function of altitude. Stereo-SCIDAR is a high-resolution stereoscopic instrument dedicated to this measure. Here, its profiles are directly compared to internal AO telemetry atmospheric profiling techniques for CANARY (Vidal et al. 2014¹), a Multi-Object AO (MOAO) pathfinder on the William Herschel Telescope (WHT), La Palma. In total twenty datasets are analysed across July and October of 2014. Levenberg-Marquardt fitting algorithms dubbed Direct Fitting and Learn 2 Step (L2S; Martin 2014²) are used in the recovery of profile information via covariance matrices - respectively attaining average Pearson product-moment correlation coefficients with stereo-SCIDAR of 0.2 and 0.74. By excluding the measure of covariance between orthogonal Wavefront Sensor (WFS) slopes these results have revised values of 0.65 and 0.2. A data analysis technique that combines L2S and SLODAR is subsequently introduced that achieves a correlation coefficient of 0.76.

Optical turbulence characterisation is crucial to understanding astronomical site and observational limitations. The Differential Image Motion Monitor (DIMM) is a widely used, low cost and portable instrument for measuring the total integrated seeing. We have designed and tested a variation on the DIMM design that utilises a low order Shack-Hartmann (SH) lenslet array instead of the standard two hole aperture mask. This instrument, which is comprised of readily available components, is known as SHIMM. This alternative design utilises more of the telescope aperture, in comparison to the DIMM, and therefore increases the signal to noise ratio, as well as providing a more accurate method of noise estimation. In future the instrument will be developed to provide estimation of the coherence timescale, limited turbulence altitude information, and to correct for scintillation effects on the seeing measurements. We describe the instrument and present measurements from two identical SHIMM seeing monitors, as well as a comparison with simultaneous optical turbulence profiles recorded with Stereo-SCIDAR on the 2.5m Isaac Newton Telescope, La Palma.

Mechanical vibrations affect the performance in modern adaptive optics systems. These structural vibrations induce aberration mainly in tip-tilt modes that reduce the accuracy of the astronomical instrument. Therefore, control actions need to be taken. With this purpose we present a laboratory demonstration of vibration rejection of tip-tilt modes using closed-loop control, inducing vibration on the test bench via an eccentric motor with controllable frequency, in order to simulate the structural vibrations mentioned above. We measure the laser vibration and its tip-tilt aberration using a camera and a Shack Hartmann Wave Front Sensor. The control action is carried out by a Fast Steering Mirror (FSM).

Frequency-based analysis and comparisons of tip-tilt on-sky data registered with 6.5 Magellan Telescope Adaptive Optics (MagAO) system on April and Oct 2014 was performed. Twelve tests are conducted under different operation conditions in order to observe the influence of system instrumentation (such as fans, pumps and louvers). Vibration peaks can be detected, power spectral densities (PSDs) are presented to reveal their presence. Instrumentation-induced resonances, close-loop gain and future challenges in vibrations mitigation techniques are discussed.

We develop an algorithm to retrieve mesospheric Na profiles from the ESO-IAC LGS experiment at Teide Observatory (OT). We are using a bistatic configuration for Na LGS profiling between the ESO Wendelstein LGS Unit (WLGSU) and the IAC80 telescope with a baseline of 126 m. We describe the geometry of the problem and discuss the errors. The inputs are the observer pointing coordinates and the azimuth of the launcher, avoiding the refraction effect on the beam. Accuracy in the coordinates is a must and the images should be astrometrized. With an accuracy of 1" in the launcher azimuth, the absolute Na heights can be obtained with a resolution better than 200 m (ZD=40°). We also propose a double observer telescope, 90° shifted, to avoid the effect of a divergent solution when launching in the azimuth subtended between observer and launcher.

In large telescopes like the E-ELT, the performance of the Adaptive Optics (AO) system is not only dominated by atmospheric disturbances but also by high frequency structural vibrations. Currently these vibrations are suppressed by a model-based feedback controller. When observing faint stars, the performance is reduced by a lower bandwidth because of a larger exposure time of the wavefront senor. The "control bandwidth" can be increased by an additional accelerometer-based feedforward controller, which is independent of the exposure time. This vibration suppression concept was studied in an AO end-to-end simulation and first investigations at a laboratory setup have been performed. Based on these results, we discuss the application for an on-sky testing at the LBT and an implementation in the MICADO AO.

CANARY is the Multi-Object Adaptive Optics (MOAO) pathfinder for the future MOAO-assisted Integral-Field Units (IFU) proposed for Extremely Large Telescopes (ELT). The MOAO concept relies on tomographically reconstructing the turbulence using multiple measurements along different lines of sight.

Tomography requires the knowledge of the statistical turbulence parameters, commonly recovered from the system telemetry using a dedicated profiling technique. For demonstration purposes with the MOAO pathfinder CANARY, this identification is performed thanks to the Learn & Apply (L&A) algorithm, that consists in model-fitting the covariance matrix of WFS measurements dependant on relevant parameters: C_n²(h) profile, outer scale profile and system mis-registration.

We explore an upgrade of this algorithm, the Learn 3 Steps (L3S) approach, that allows one to dissociate the identification of the altitude layers from the ground in order to mitigate the lack of convergence of the required empirical covariance matrices therefore reducing the required length of data time-series for reaching a given accuracy. For nominal observation conditions, the L3S can reach the same level of tomographic error in using five times less data frames than the L&A approach.

The L3S technique has been applied over a large amount of CANARY data to characterize the turbulence above the William Herschel Telescope (WHT). These data have been acquired the 13th, 15th, 16th, 17th and 18th September 2013 and we find 0.67"/8.9m/3.07m.s⁻¹ of total seeing/outer scale/wind-speed, with 0.552"/9.2m/2.89m.s⁻¹ below 1.5 km and 0.263"/10.3m/5.22m.s⁻¹ between 1.5 and 20 km. We have also determined the high altitude layers above 20 km, missed by the tomographic reconstruction on CANARY , have a median seeing of 0.187" and have occurred 16% of observation time.

ARGOS is the Ground Layer Adaptive Optics system of the Large Binocular Telescope, it uses three Laser Guide Stars, generated by Rayleigh backscattered light of pulsed lasers. Three Shack-Hartmann WFS measure the wavefront distortion in the Ground Layer. The SLOpe Detection And Ranging (SLODAR) is a method used to measure the turbulence profiles. Cross correlation of wavefronts gradient from multiple stars is used to estimate the relative strengths of turbulent layers at different altitudes. We present here the results on sky of the SLODAR profile on ARGOS.

The estimations of the Fried parameter according to micrometeorological and optical measurements in the atmospheric surface layer in the area of l. Baikal, Baikal astrophysical Observatory (BAO). According to the archive of NCEP/NCAR Reanalysis data obtained vertical distribution of temperature pulsations, and revealed the most pronounced atmospheric layers with high turbulence. It is established that the values of the fried parameter at the location of the BAO are in the range from 1.5 to 5.5 cm in inter, the atmospheric coherence radius is characterized by low values of the Fried parameter. Turbulyzed atmospheric layers of the atmosphere located at an altitude of about 2.5 km and 11.5 km above the observatory, respectively. The average values of the fried radius is 4.6 cm.

In this paper we present numerical simulations and an initial design for a visible MCAO system for the VLT-UT4 telescope. The proposed concept takes great advantage of the existing HW developed for the Adaptive Optics Facility (AOF) at the VLT-UT4, in particular the 4x20W Toptica lasers and the adaptive secondary mirror with 1170 actuators. The mentioned units makes the VLT-AOF a unique facility to develop a second generation AO system aiming to provide corrected FoV at short wavelength. In particular the flux provided by the four lasers steerable on sky and the high density of actuators (20cm equivalent on M1) provides the temporal bandwidth and the spatial sampling to push the correction down to the visible wavelengths. In addition to this the request of a reasonable size corrected FoV with uniform performance calls for an MCAO system. For such reason here we propose to complement the AOF with post-focal DMs that together with the VLT DSM can provide a corrected FoV of roughly 20/30 arcsec diameter size. An additional challenge for the system is the provided a large sky coverage. Such condition comes from the efficiency of LO wavefront sensors that use field NGS. The presented simulations give some first results for (a) the achieved performance at visible wavelength 0.4-0.9 um as a function of DMs and tip tilt NGSs characteristics (b) the achieved system sky coverage after. Pushing performance toward visible wavelengths calls for embedded and efficient post-processing methods. Being able to capture short-exposure science images (with the trade-off on noise and overheads), would allow retrieving the ultimate performance by compensating the residual turbulence aberrations left over by the AO system. Considerations about advanced analysis tools that may potentially relax the system constraints are discussed. Finally the paper presents a conceptual arrangement for the opto-mechanics of the considered AO module including the additional DMs and wavefront sensors.

We present here SOUL: the Single conjugated adaptive Optics Upgrade for LBT. Soul will upgrade the wavefront sensors replacing the existing CCD detector with an EMCCD camera and the rest of the system in order to enable the closed loop operations at a faster cycle rate and with higher number of slopes. Thanks to reduced noise, higher number of pixel and framerate, we expect a gain (for a given SR) around 1.5–2 magnitudes at all wavelengths in the range 7.5 <mR <18. The correction at short wavelength will be greatly improved (SR>70% in I-band and 0.6asec seeing) and the sky coverage will be multiplied by a factor 5 at all galactic latitudes. Upgrading the SCAO systems at all the 4 focal stations, SOUL will provide these benefits in 2017 to the LBTI interferometer and in 2018 to the 2 LUCI NIR spectro-imagers. In the same year the SOUL correction will be exploited also by the new generation of LBT instruments: V-SHARK, SHARK-NIR and iLocater.

Millisecond focal plane telemetry is now becoming practical due to a new generation of near-IR detector arrays with sub-electron noise that are capable of kHz readout rates. Combining these data with those simultaneously available from the wavefront sensing system allows the possibility of self-consistently determining the optical aberrations (the cause of quasi-static speckles) and the planetary image. This approach may be especially advantageous for finding planets within about 3λ/D of the star where differential imaging is ineffective. As shown in a recent article by the author (J. Opt. Soc. Am. A., 33, 712, 2016), one must account for unknown aberrations in several non-conjugate planes of the optical system, which, in turn, requires ability to computational propagate the field between these planes. These computations are likely to be difficult to implement and expensive. Here, a far more convenient alternative based on empirical Green's functions is provided. It is shown that the empirical Green's function (EGF), which accounts for all multi-planar, non-common path aberrations, and results in a much more tractable and highly parallel computational problem. It is also shown that the EGF can be generalized to treat polarization, resulting in the empirical Green's tensor (EGT).

We introduced the use of Artificial Neural Networks (ANN) for centroiding in Shack-Hartmann wavefront sensors in the presence of elongated spots, as it will occur in Extremely Large Telescopes. We showed in simulation that ANNs can outperform existing techniques, such as the Matched Filter. The main advantage of our technique is its ability to cope with changing conditions, as real atmospheric turbulence behaves. Here we present experimental results from the laboratory that confirm the findings in our original article, while at the same time they are useful to refine the ANN-based techniques.

The Southern Robotic Adaptive Optics (SRAO) instrument will bring the proven high-efficiency capabilities of Robo-AO to the Southern-Hemisphere, providing the unique capability to image with high-angular-resolution thousands of targets per year across the entire sky. Deployed on the modern 4.1m SOAR telescope located on Cerro Tololo, the NGS AO system will use an innovative dual-knife-edge wavefront sensor, similar to a pyramid sensor, to enable guiding on targets down to V=16 with diffraction limited resolution in the NIR. The dual-knife-edge wavefront sensor can be up to two orders of magnitude less costly than custom glass pyramids, with similar wavefront error sensitivity and minimal chromatic aberrations. SRAO is capable of observing hundreds of targets a night through automation, allowing confirmation and characterization of the large number of exoplanets produced by current and future missions.

Chinese Giant Solar Telescope (CGST) is the next generation infrared and optical solar telescope of China, which is proposed and pushed by the solar astronomy community of China and listed into the National Plans of Major Science and Technology Infrastructures. CGST is currently proposed to be an 8 meter Ring Solar Telescope (RST) with width of 1 meter, the hollow and symmetric structure of such an annular aperture facilitates the thermal control and high precision magnetic field measurement for a solar telescope. Adaptive optics (AO) is an indispensable tool of RST to obtain diffraction limited observations. How to realize AO involved wavefront sensing and correcting, and the degree of compensating in a narrow annular aperture is the primary problem of AO implementation of RST. Wavefront reconstruction involved problems of RST are first investigated and discussed in this paper using end to end simulation based on Shack-Hartmann wavefront sensing (SHWFS). The simulation results show that performance of zonal reconstruction with measurement noise no more than 0.05 arc sec can meets the requirement of RST for diffraction-limited imaging at wavelength of 1μm, which satisfies most science cases of RST in near infrared waveband.

Radial velocity instruments require high spectral resolution and extreme thermo-mechanical stability, even more difficult to achieve in near-infra red (NIR) where the spectrograph has to be cooled down. For a seeing-limited spectrograph, the price of high spectral resolution is an increased instrument volume, proportional to the diameter of the primary mirror. A way to control the size, cost, and stability of radial velocity spectrographs is to reduce the beam optical etendue thanks to an Adaptive Optics (AO) system. While AO has revolutionized the field of high angular resolution and high contrast imaging during the last 20 years, it has not yet been (successfully) used as a way to control spectrographs size, especially in the field of radial velocities.

In this work we present the AO module of the future NIRPS spectrograph for the ESO 3.6 m telescope, that will be feed with multi-mode fibers. We converge to an AO system using a Shack-Hartmann wavefront sensor with 14x14 subapertures, able to feed 50% of the energy into a 0.4" fiber in the range of 0.98 to 1.8 μm for M-type stars as faint as I=12.

Deformable mirror is a widely used wavefront corrector in adaptive optics system, especially in astronomical, image and laser optics. A new structure of DM--3D DM is proposed, which has removable actuators and can correct different aberrations with different actuator arrangements. A 3D DM consists of several reflection mirrors. Every mirror has a single actuator and is independent of each other. Two kinds of actuator arrangement algorithm are compared: random disturbance algorithm (RDA) and global arrangement algorithm (GAA). Correction effects of these two algorithms and comparison are analyzed through numerical simulation. The simulation results show that 3D DM with removable actuators can obviously improve the correction effects.

The use of sodium laser guide star for Extremely Large Telescopes (ELT) adaptive optics systems is a key concern due to the perspective effect that produces elongated images in the Shack-Hartmann pattern. In order to assess the feasibility of using an elongated sodium beacon on an ELT, an on-sky experiment reproducing the extreme off-axis launch conditions of the European ELT is scheduled for summer and autumn 2016. The experiment will use the demonstrator CANARY installed on the William Herschel Telescope and the ESO transportable 20W CW fiber laser, embedded in the Wendelstein LGS unit. We will discuss here the challenges this experiment addresses as well as the details of its implementation and the derivation of the error budget.

The GMT is an aplanatic Gregorian telescope consisting of 7 primary and secondary mirror segments that must be phased to within a fraction of an imaging wavelength to allow the 25.4 meter telescope to reach its diffraction limit. When operating in Laser Tomographic Adaptive Optics (LTAO) mode, on-axis guide stars will not be available for segment phasing. In this mode, the GMT’s Acquisition, Guiding, and Wavefront Sensing system (AGWS) will deploy four pickoff probes to acquire natural guide stars in a 6-10 arcmin annular FOV for guiding, active optics, and segment phasing. The phasing sensor will be able to measure piston phase differences between the seven primary/secondary pairs of up to 50 microns with an accuracy of 50 nm using a J-band dispersed fringe sensor. To test the dispersed fringe sensor design and validate the performance models, SAO has built and commissioned a prototype phasing sensor on the Magellan Clay 6.5 meter telescope. This prototype uses an aperture mask to overlay 6 GMT-sized segment gap patterns on the Magellan 6.5 meter primary mirror reimaged pupil. The six diffraction patterns created by these subaperture pairs are then imaged with a lenslet array and dispersed with a grism. An on-board phase shifter has the ability to simulate an arbitrary phase shift within subaperture pairs. The prototype operates both on-axis and 6 arcmin off-axis either with AO correction from the Magellan adaptive secondary MagAO system on or off in order to replicate as closely as possible the conditions expected at the GMT.

In the context of ADONI, the newly constituted laboratory for INAF Adaptive Optics activities, it is foreseen to set-up a facility accessible to the Italian and international AO community, with the purpose of facilitating the testing of critical sub-systems or components (which may be part of instruments under construction), or prototypes of innovative concepts which may require on-sky demonstrations. The 182cm Copernico Telescope located in Asiago (Italy) has been selected to be a suitable place to set-up this public facility, where a common optical bench will be made available at the Coudé focus to host visiting instrumentation. In this paper we describe the opto-mechanical train to the Coudé focal station to be implemented for the laboratory set-up, and we sketch out the foreseen telescope refurbishing activities to implement this multi-purpose testing facility dedicated to AO related projects.

CHOUGH is a small, fast project to provide an experimental on-sky high-order SCAO capability to the 4.2m WHT telescope. The basic goal has r₀-sized sub- apertures with the aim of achieving high-Strehl ratios (> 0:5) in the visible (> 650 nm). It achieves this by including itself into the CANARY experiment: CHOUGH is mounted as a breadboard and intercepts the beam within CANARY via a periscope. In doing so, it takes advantage of the mature CANARY infrastructure, but add new AO capabilities. The key instruments that CHOUGH brings to CANARY are: an atmospheric dispersion compensator; a 32 × 32 (1000 actuator) MEMS deformable mirror; 31 × 31 wavefront sensor; and a complementary (narrow-field) imager. CANARY provides a 241-actuator DM, tip/tilt mirror, and comprehensive off-sky alignment facility together with a RTC. In this work, we describe the CHOUGH sub-systems: backbone, ADC, MEMS-DM, HOWFS, CAWS, and NFSI.

The laboratory test bench HeNOS is a scaled down version of TMTs first light MCAO instrument NFIRAOS, it is designed to mimic the behavior within the limits of a lab. Its purpose is the verification of the performance predicted through simulations and the demonstration of calibration procedures. The MCAO correction includes LGS effects like spot elongation, tip/tilt uncertainty and sodium layer variations. Tests contain turbulent layer identification with SLODAR, tomographic NCPA correction, matched filter updates, a Pyramid Truth WFS and PSF reconstruction. We discuss the recent advances on the tests and the impact of the results on the control of NFIRAOS.

An astronomical adaptive optics test-bench, designed to replicate the conditions of a 4 m-class telescope, is presented. Named DRAGON-Next Generation, it is constructed primarily from commercial off-the-shelf components with minimal customization (approximately a 90:10 ratio). This permits an optical design which is modular and this leads to a reconfigurability. DRAGON-NG has been designed for operation for the following modes: (high-order) SCAO, (twin-DM) MOAO, and (twin-DM) MCAO. It is capable of open-loop or closed-loop operation, with (3) natural and (3) laser guide-star emulation at loop rates of up to 200Hz. Field angles of up-to 2.4 arcmin (4m pupil emulation) can pass through the system. The design is dioptric and permits long cable runs to a compact real-time control system which is on-sky compatible. Therefore experimental validation can be carried out on DRAGON-NG before transferring to an on-sky system, which is a significant risk mitigation.

AutoCAD, Zemax Optic Studio 15, and Interactive Data Language (IDL) with the Proper Library are used to computationally model and test a diffractive mask (DiM) suitable for use in the Gemini Multi-Conjugate Adaptive Optics System (GeMS) on the Gemini South Telescope. Systematic errors in telescope imagery are produced when the light travels through the adaptive optics system of the telescope. DiM is a transparent, flat optic with a pattern of miniscule dots lithographically applied to it. It is added ahead of the adaptive optics system in the telescope in order to produce diffraction spots that will encode systematic errors in the optics after it. Once these errors are encoded, they can be corrected for. DiM will allow for more accurate measurements in astrometry and thus improve exoplanet detection. The mechanics and physical attributes of the DiM are modeled in AutoCAD. Zemax models the ray propagation of point sources of light through the telescope. IDL and Proper simulate the wavefront and image results of the telescope. Aberrations are added to the Zemax and IDL models to test how the diffraction spots from the DiM change in the final images. Based on the Zemax and IDL results, the diffraction spots are able to encode the systematic aberrations.

Extreme adaptive optics (XAO) systems have severe difficulties to meet the following high contrast requirements: high speed (>1kHz) and high accuracy (∼10 nm) at 5-10 cm spatial scale. An innovative high order adaptive optics system using a self-referenced Mach-Zehnder wavefront sensor has been proposed to counteract these limitations. This wavefront sensor estimates the phase by measuring directly intensity differences between two outputs, but has a limited dynamical range. In this paper, we report on our latest results with the XAO testbed in operation in our lab, and dedicated to high contrast imaging with 30m-class telescopes. A woofer-tweeter architecture is used in order to deliver the required high Strehl ratio (>95%). We present our latest laboratory results, including fine calibration and closed loop performance. This work is carried out in synergy with the validation of fast iterative wavefront reconstruction algorithms, and the optimal treatment of phase ambiguities in order to mitigate the dynamical range limitation of such a wavefront sensor.

This paper presents the early-stage simulation results of linear dark field control (LDFC) as a new approach to maintaining a stable dark hole within a stellar post-coronagraphic PSF. In practice, conventional speckle nulling is used to create a dark hole in the PSF, and LDFC is then employed to maintain the dark field by using information from the bright speckle field. The concept exploits the linear response of the bright speckle intensity to wavefront variations in the pupil, and therefore has many advantages over conventional speckle nulling as a method for stabilizing the dark hole. In theory, LDFC is faster, more sensitive, and more robust than using conventional speckle nulling techniques, like electric field conjugation, to maintain the dark hole. In this paper, LDFC theory, linear bright speckle characterization, and first results in simulation are presented as an initial step toward the deployment of LDFC on the UA Wavefront Control testbed in the coming year.

Sky-coverage in laser-assisted AO observations largely depends on the system's capability to guide on the faintest natural guide-stars possible. Here we give an up-to-date status of our natural guide-star processing tailored to the European-ELT's visible and near-infrared (0.47 to 2.45 μm) integral field spectrograph — Harmoni.

We tour the processing of both the isoplanatic and anisoplanatic tilt modes using the spatio-angular approach whereby the wavefront is estimated directly in the pupil plane avoiding a cumbersome explicit layered estimation on the 35-layer profiles we're currently using.

Taking the case of Harmoni, we cover the choice of wave-front sensors, the number and field location of guide-stars, the optimised algorithms to beat down angular anisoplanatism and the performance obtained with different temporal controllers under split high-order/low-order tomography or joint tomography. We consider both atmospheric and far greater telescope wind buffeting disturbances. In addition we provide the sky-coverage estimates thus obtained.

The main goal of Green Flash is to design and build a prototype for a Real-Time Controller (RTC) targeting the European Extremely Large Telescope (E-ELT) Adaptive Optics (AO) instrumentation. The E-ELT is a 39m diameter telescope to see first light in the early 2020s. To build this critical component of the telescope operations, the astronomical community is facing technical challenges, emerging from the combination of high data transfer bandwidth, low latency and high throughput requirements, similar to the identified critical barriers on the road to Exascale. With Green Flash, we will propose technical solutions, assess these enabling technologies through prototyping and assemble a full scale demonstrator to be validated with a simulator and tested on sky. With this R&D program we aim at feeding the E-ELT AO systems preliminary design studies, led by the selected first-light instruments consortia, with technological validations supporting the designs of their RTC modules. Our strategy is based on a strong interaction between academic and industrial partners. Components specifications and system requirements are derived from the AO application. Industrial partners lead the development of enabling technologies aiming at innovative tailored solutions with potential wide application range. The academic partners provide the missing links in the ecosystem, targeting their application with mainstream solutions. This increases both the value and market opportunities of the developed products. A prototype harboring all the features is used to assess the performance. It also provides the proof of concept for a resilient modular solution to equip a large scale European scientific facility, while containing the development cost by providing opportunities for return on investment.