High resolution imaging of wide fields has been a prerogative of space telescopes for decades. Multi-conjugate adaptive optics (MCAO) is a key technology for the future of ground-based astronomy, especially as we approach the era of ELTs, where the large apertures will provide diffraction limits that will significantly surpass even the James Webb Space Telescope. NFIRAOS will be the first light MCAO system for the Thirty Meter Telescope and to support its development I have worked on HeNOS, its test bench integrated in Victoria at NRC Herzberg. I have aligned the optics, tested the electronic hardware, calibrated the subsystems (cameras, deformable mirrors, light sources, etc.) and characterized the system parameters. Development and support for future MCAO instruments also involves data analysis, a critical process in delivering the expected performance of any scientific instrument. To develop a strategy for optimal stellar photometry with MCAO, I have observed the Galactic globular cluster NGC 1851 with GeMS, the MCAO system on the 8-meter Gemini South telescope. From near-infrared images of this target in two bands, I have found the optimal parameters to employ in the profile-fitting photometry and calibration. As testimony to the precision of the results, I have obtained the deepest near-infrared photometry of a crowded field from the ground and used it to determine the age of the cluster with a method recently proposed that exploits the bend in the lower main sequence. The precise color-magnitude diagram also allows us to clearly observe the double subgiant branch for the first time from the ground, caused by the multiple stellar populations in the cluster. As the only facility MCAO system, GeMS is an important instrument that serves to illuminate the challenges of obtaining accurate photometry using such a system. By coupling the knowledge acquired from an instrument already on-sky with experiments in the lab on a prototype of a future system, I have addressed new challenges in photometry and astrometry, like the promising technique of point spread function reconstruction. This thesis informs the development of appropriate data processing techniques and observing strategies to ensure the ELTs deliver their full scientific promise over extended fields of view. / Graduate

The recent advent of next generation ground-based telescopes, code-named Extremely Large Telescopes (ELT), highlights the beginning of a forced march toward an era of deploying instruments capable of exploiting starlight captured by mirrors at an unprecedented scale. This confronts the astronomy community with both a daunting challenge and a unique opportunity. The challenge arises from the mismatch between the complexity of current instruments and their expected scaling with the square of the future telescope diameters, on which astronomy applications have relied to produce better science. To deliver on the promise of tomorrow’s ELT, astronomers must design new technologies that can effectively enhance the performance of the instrument at scale, while compensating for the atmospheric turbulence in real-time. This is an unsolved problem. This problem presents an opportunity because the astronomy community is now compelled to rethink essential components of the optical systems and their traditional hardware/software ecosystems in order to achieve high optical performance with a near real-time computational response. In order to realize the full potential of such instruments, we investigate a technique supporting Adaptive Optics (AO), i.e., a dedicated concept relying on turbulence tomography. In particular, a critical part of AO systems is the supervisor module, which is responsible for providing the system with a Tomographic Reconstructor (ToR) at a regular pace, as the atmospheric turbulence evolves over an observation window. In this thesis, we implement an optimized supervisor module and assess it under real configurations of the future European ELT (E-ELT) with a 39m diameter, the largest and most complex optical telescope ever conceived. This necessitates manipulating large matrix sizes (i.e., up to 100k × 100k) that contain measurements captured by multiple wavefront sensors. To address the complexity bottleneck, we employ high performance computing software solutions based on cutting-edge numerical algorithms using asynchronous, fine-grained computations as well as approximations techniques that leverage the resulting matrix data structure. Furthermore, GPU-based hardware accelerators are used in conjunction with the software solutions to ensure reasonable time-to-solution to cope with rapidly evolving atmospheric turbulence. The proposed software/hardware solution permits to reconstruct an image with high accuracy. We demonstrate the validity of the AO systems with a third-party testbed simulating at the E-ELT scale, which is intended to pave the way for a first prototype installed on-site

The Giant Magellan Telescope (GMT) will be featured with two Gregorian secondary mirrors, an adaptive secondary mirror (ASM) and a fast-steering secondary mirror (FSM). The FSM has an effective diameter of 3.2 m and built as seven 1.1 m diameter circular segments, which are conjugated 1:1 to the seven 8.4m segments of the primary. Each FSM segment contains a tip-tilt capability for fine co-alignment of the telescope subapertures and fast guiding to attenuate telescope wind shake and mount control jitter. This tip-tilt capability thus enhances performance of the telescope in the seeing limited observation mode. As the first stage of the FSM development, Phase 0 study was conducted to develop a program plan detailing the design and manufacturing process for the seven FSM segments. The FSM development plan has been matured through an internal review by the GMTO-KASI team in May 2016 and fully assessed by an external review in June 2016. In this paper, we present the technical aspects of the FSM development plan.

L’ELT (Extremely Large Telescope), est un télescope de diamètre 39 m en cours de réalisation par l’Observatoire Européen Austral (ESO). Pour pouvoir tirer pleinement parti de sa taille, ses instruments seront équipés de systèmes d’Optique Adaptative (OA) qui compenseront la turbulence atmosphérique. Ces systèmes d’OA requièrent l’utilisation d’étoiles guides laser afin de maximiser la couverture du ciel. Les étoiles guides laser sont générées par laser accordé sur une résonance d’atome de sodium présents dans une couche d’une épaisseur de 10 km et située à environ 90 km d’altitude. Une étoile laser est donc un cylindre lumineux dans la haute atmosphère, allumé par la relaxation des atomes. L’analyse de front d’onde à l’aide de ces étoiles artificielles souffrent de limitations connues. De plus, sur un télescope de la taille de l’ELT, leur utilisation est compliquée par l’effet de perspective qui provoque un allongement de l’étoile guide lorsqu’elle est vue d’un point éloigné de son point de lancement au sol : le cylindre n’est plus vu par une section circulaire, mais sur le côté. Sur un télescope de 39m, l’élongation de l’étoile peut alors atteindre jusqu’à 20 secondes d’arc, à comparer avec le diamètre du cylindre qui est déterminé par la turbulence, soit de l’ordre d’une seconde d’arc. La variabilité de l’épaisseur, de l’altitude et de la distribution de densité de la couche de sodium ont alors un impact sur la mesure du front d’onde.L’étude de ce problème, qui porte à la fois sur les algorithmes de mesure et le design des analyseurs de front d’onde, a donné lieu à de nombreux travaux s’appuyant sur des simulations et des tests en laboratoire. Le but de cette thèse a été d’étudier cette question à l’aide de données expérimentales obtenues sur le ciel. Ces données ont été enregistrées grâce au démonstrateur d’OA CANARY, situé sur le télescope William Herschel sur l’île de la Palma aux Canaries. CANARY a été développé par le LESIA, en collaboration avec l’Université de Durham; le laser et son télescope d’émission ont été fournis et opéré par l’ESO. Lors de cette expérience, l'allongement extrême des étoiles laser qui sera observé sur l'ELT a été reproduit en plaçant le télescope d’émission à environ 40m du télescope William Herschel. Le front d'onde a ensuite été mesuré sur l’étoile laser allongée ainsi crée.Les travaux effectués pendant cette thèse ont consisté en la préparation de l’instrument et en particulier de l’analyseur de front d’onde de l’étoile laser, la réalisation des observations et le traitement des données résultant de ces dernières. L’analyse de ces données a permis de construire un budget d’erreur de la mesure de front d’onde sur étoile laser allongée. Grâce à ce budget d’erreur, les performances de différents algorithmes de mesure ont été comparées, ainsi que leur comportement face à la variabilité du profil de sodium et des conditions de turbulence. Enfin, différentes configurations d’analyseurs ont été extrapolées, ce qui a permis d’établir des limites sur leur design dans le cadre de l’ELT. / The ELT (Extremely Large Telescope) is a telescope whose diameter is 39 m currently under construction by the European Southern Observatory (ESO). In order to fully benefit from its size, ELT instruments will be equipped with Adaptive Optics (AO) systems to compensate the atmospheric turbulence. These AO systems require the use of Laser Guides Stars (LGS) in order to have as large a sky coverage as possible. LGS are generated using a laser tuned on a resonant frequency of sodium atoms contained in a layer approximately 90km high and 10 km thick. Therefore, a LGS is a luminous cylinder in the high atmosphere, lighted by sodium atoms relaxation. Wavefront sensing on these artificial stars suffers from known limitations. On a telescope the size of the ELT, their use is further complicated by the perspective effect which causes an elongation of the LGS when it is seen from a point distant from its launch position : the cylinder is no longer seen by its circular section, but on the side. On a 39m telescope, the elongation can reach up to 20 arcseconds, which is large compared to to the diameter of the cylinder determined by the turbulence, that is about 1 arcsecond. Variability of the thickness, height and density distribution of the sodium layer then have an impact on wavefront sensing. The study of this problem, which concerns both sensing algorithms and wavefront sensor design, has already been the subject of many work relying on simulations and laboratory experiments. This thesis aims at studying this question using experimental data obtained on sky. These data were acquired using the AO demonstrator CANARY, placed on the William Herschel Telescope (WHT) on the island of La Palma in the Canaries Island. CANARY was developed by LESIA in collaboration with Durham University; the laser and its launch telescope were supplied and operated by ESO. In this experiment, the extreme elongation of LGS as will be seen on the ELT was reproduced by placing the launch telescope 40 m away from the William Herschel Telescope. The wavefront was the measured on the elongated LGS thus created. The studies led during this thesis consisted in the preparation of the instrument and in particular the LGS Wavefront Sensor (WFS), the realisation of the observations and processing on the data obtained. Analysis of these data allowed to build an error breakdown of wavefront sensing on the elongated LGS. Thanks to this error breakdown, performances of different measurement algorithms where compared, as well as their behaviour according to the variability of the sodium profile and the turbulence conditions. Finally, different wavefront sensor designs were extrapolated which allowed to establish limits on their designs for the ELT.

This thesis presents a simulation of the control system for Laser Guide Star (LGS) wavefront sensing of the Narrow Field Infrared Adaptive Optics System (NFIRAOS) which will be the Adaptive Optics (AO) system on the Thirty Meter Telescope. The control system is multirate and combines data from multiple sources, both natural and artificial, to provide wavefront correction. Artificial guide stars are generated by exciting atoms in the mesospheric sodium (Na) layer. The characteristics of the Na layer have been examined; its variability, altitude and thickness will lead to false atmospheric turbulence measurements by AO systems integrated with Extremely Large Telescopes. A periodically updated constrained matched filter algorithm has been implemented in the control system simulation in order to gauge its ability to mitigate these effects. The control system has also been implemented on the University of Victoria LGS Test Bench which reproduces wavefront measurements as they will be made by several of the wavefront sensors of NFIRAOS. The simulation has provided insight into the stability of the proposed control system and allowed necessary improvements to be made. It has been shown to meet the requirements of stability over long term with fast convergence. The matched filter algorithm has been shown to effectively reject the Na layer fluctuations both in simulation and on the test bench.