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The Giant Magellan Telescope (GMT) is a gregorian 25.5-meter diameter primary mirror (M1) made of 7 8.4-meter diameter circular aspheric segments. The secondary mirror (M2) is a 1/8th down-scale model of M1 madeof 7 1- meter diameter segments. Each segments has positionners to adjust its 6 rigid body motions. The gureof M1 segment is controlled with 44 bending modes and M2 segments are deformed using 672 actuators. Inthe active and adaptive operation modes of the GMT, around a dozen wavefront sensors (WFS) are selectivelyused to monitor the optical aberrations building-up into the telescope. A dedicated control system feeds backthe WFS measurements to the mirrors actuators to deliver image quality optimized for the eld of view of eachscientic instrument. This paper describes the GMT Dynamic Optical Simulation (DOS) tool. DOS integratesthe optical and mechanical model of the telescope together with the control system. DOS is a cloud-basedoptical propagation software package with build-in models for both geometric and Fourier optics and a fullcontrol algorithm development environment.

The SPHERE instrument (Beuzit, et al., 2010) is dedicated to the direct imaging of extra-solar planets. This kind of observation allows one to study the photons emitted by the planet’s atmosphere itself, or reflected by its surface. The search for bio-markers is therefore made possible. The SPHERE instrument has been installed and commissioned at VLT Paranal Observatory during 2014 and now routinely delivers high contrast images to the exoplanet community. This paper presents a study of the main actual limitation of the SPHERE instrument, as known as the Low Wind Effect [LWE]. This effect has been discovered on SPHERE during commissioning period. Its effect is a strong degradation of the instrument PSF, preventing instrument to perform high contrast imaging. It happens during particularly low wind conditions (below 1m/s at the telescope level) which happens one night out of five.

The time evolution of the sodium profile greatly impact the accuracy of laser guide star (LGS) wavefront sensor (WFS) measurements, for either the traditional thresholded center of gravity or the more advanced constraint matched filter/correlation algorithms. As a result, circularly symmetric wavefront aberrations will be induced in the adaptive optics (AO) corrected science wavefront for center launch LGS. In this paper, we describe our scheme to mitigate this issue by updating pixel processing parameters and employing a truth WFS during LGS AO operation. We also present simulation results using the sodium profiles measured by the UBC lidar. In addition, the time evolution of the turbulence profile will also have an impact on the pixel processing accuracy for the advanced algorithms, as well as the minimum variance wavefront reconstruction. We present simulation results showing how often we have to update the corresponding parameters to minimize the effect.

The laser guide star (LGS) adaptive optics (AO) system on the Keck II telescope has been upgraded with a Center Launch Laser System (CLS) and a next generation laser (NGL; i.e. a TOPTICA/MPBC laser) is being implemented. The purpose of the CLS upgrade is to improve the performance of the existing Keck II LGS AO system by reducing the perspective elongation of the LGS as seen by the AO wavefront sensor and hence the measurement error, one of the largest terms in the current error budget. This performance improvement is achieved by projecting the laser from behind the Keck telescope’s secondary mirror instead of from the side of the Keck telescope. The purpose of the NGL upgrade is to increase the laser return and improve laser operability for science operation. The higher return from the NGL would open up new possibilities for further AO upgrades such as a laser asterism to reduce the focal anisoplanatism, and to increase the wavefront sensor (WFS) sampling rate to reduce the bandwidth error in addition to reducing the measurement error.The CLS transitioned to science operation in June 2015. The NGL with the CLS had first light on Dec. 1, 2015 and is being optimized to support transitioning to science operations in April 2016. This paper provides an overview of the design, implementation and on-sky performance of the new launch system and laser. The results are discussed in the context of AO for extremely large telescopes.

In this paper, we present a tomographic reconstruction method to reduce a tomographic error, multi time-stepreconstruction, for a wide-eld adaptive optics (WFAO). Based on the frozen ow assumption, we can computethe time evolution of measurements from wave-front sensors (WFS) at previous time-steps with using windinformation. Our idea is to reduce the tomographic error by using the measurements at both the current andprevious time-steps simultaneously. We also develop a method to estimate wind speed and direction at eachaltitude from temporal correlations of phase distortion pattern reconstructed by a classical tomography. Weevaluate the performance of the method by a laboratory experiment with the RAVEN, a multi-object adaptiveoptics (MOAO) technical and science demonstrator. In the laboratory experiment, our wind estimation methodcan estimate wind speeds and directions of multiple layers. By the multi time-step reconstruction method, theensquared energy in a 140 mas box increases about 3{5% compared with a classical tomographic reconstruction.

ARGOS is the laser guide star facility of the Large Binocular Telescope (LBT). It implements a Rayleigh Laser Guide Star system that provides Ground Layer Adaptive Optics (GLAO) correction for the LUCIs, the 2 wide- field near-infrared imagers and multi-object spectrographs installed on the 2 eyes of LBT. In this paper we describe how LBT’s adaptive optics operations have been tailored to ARGOS’s use cases based on the experience developed during over the ARGOS commissioning. We focus on all the aspects that are influenced by the use of the Laser Guide Stars, from collimation to acquisition and LGS guiding and we details the sequences to start, pause and resume the adaptive correction.

We present the final development of our point spread function reconstruction algorithm for the Keck-II telescope adaptive optics system, in laser and natural guide star modes. The method makes use of AO loop teleme- try, nearby CN2 profiler data, and on-sky phase diversity. We describe the fundamental assumptions and the mathematical models for each components of the residual phase structure function. The reconstructed PSF is compared with on-sky single star PSF. We emphasize the importance of access to a good telemetry and the fact that non-common path aberrations also affects PSF-R. The global, statistical quality of the reconstructed PSF demonstrates the validity of the method. The algorithm is now ready for AO science data reduction (see the companion overview paper, Ragland et al.1 - this conference).

In this paper, we discuss the feasibility and the performance assessment of a possible MCAO system for E-ELT, basedon the novel concept of Global MCAO, which takes advantage of a very wide technical FoV to perform adaptive opticscorrection using only natural guide stars, with the aim to increase the sky coverage. The technique envisages thedefinition of Virtual-DMs, as tools for the global reconstruction. This investigation has been carried out during afeasibility study we performed for ESO, in which we combined computations, simulations and literature. The aim of thisanalysis is to identify and review the main parameters and the technical issues, which would act as error sources in a realGMCAO system, evaluating their contribution to the overall performance. The study involves both issues related to thePyramid WFS in general, and to the GMCAO case in particular, including the wavelength and FoV size selection, thenumber of guide stars and reconstructed Virtual-DMs, and actual components parameters.