Multi-Object Adaptive Optics (MOAO) is an adaptive optics technique being developed for Extremely Large Telescopes that will allow simultaneous observation of approximately 20 targets in a several arc-minute field of regard. Raven is an MOAO pathfinder developed by the Adaptive Optics Laboratory of the University of Victoria, in collaboration with the National Research Council of Canada and the Subaru Telescope. It will be the first MOAO instrument on a 8-m class telescope, will demonstrate that MOAO technical challenges such as open-loop control and calibration are achievable on-sky and will deliver science results using three natural guide stars and two science arms on ∼ 3.5′ field-of-regard. The open-loop approach makes the need for calibration even more crucial. An important part of the calibration process resides in the misregistration of the wavefront sensors (WFSs) with the deformable mirrors (DMs) because the sensing elements are located before the correcting ones. This problem is solved using a cal- ibration DM seen by all WFSs in the system that permits the open-loop WFS to be registered to the science DMs. The method developed in this thesis registers the position of the DM actuators to the WFSs and gives misregistration values. These results are then used to better align the instrument, to have a better knowledge of the positions of the different optical components and generate new ways to perform the AO correction. Using the registration parameters results, synthetic interaction matrices are created in order to improve the AO correction. Calibration tests are also presented in this thesis. They show complementary tests to the expected requirements to expand the knowledge of the calibration unit behaviour. / Graduate / 0548 / 0752 / lpham@uvic.ca

The aim of this thesis has been summarized as the design of a micro-satellite camera system and its focal plane simulations. The average micro-satellite orbit heights ranges in between 600-850 km and obviously a multipayload satellite brings volume and power restrictions for each payload. In this work, an orbit height of 600 km and a volume of 20&times / 20&times / 30 cm is assumed, since minimizing the payload dimensions increases the probability of the launch. The pixel size and the dimensions of an imaging detector such as charge-coupled device (CCD) have been defined by the useful image area with acceptable aberration limits on the focal plane. In order to predict the minimum pixel size to be used at the focal plane modulation transfer function (MTF), point spread function (PSF), image distortion and aberration simulations have been carried out and detector parameters for the designed camera have been presented.

Thesis (Master Diploma (Electrical Engineering))-- Cape Technikon, Cape Town, 1988 / This thesis describes the control system developed to improve the efficiency of star acquisition on a ground-based optical telescope. "Star Acquisition" refers to the process of identifying the star of interest in a field of stars and centering it on the optical axis of the telescope , as well as setting an autoguider detector on a suitable star so the autoguider can improve the tracking performance of the telescope. Efficiency is improved by making all functions remote controlled , so the astronomer does not have to move between the control room and the telescope to operate the instrument.

Galileo's Eyeglass is a celebratory work for full orchestra with standard instrumentation commemorating Galileo Galilei's discoveries of the four largest moons of Jupiter and the rings of Saturn in 1610. The composition is approximately 14 minutes in duration, and although divided thematically into four parts, the music is continuous. The work exhibits primarily a blend of contemporary styles and compositional elements, yet it is rooted in traditional tonality; furthermore, the piece is interspersed with references to Galileo's life and times, including quotations of a toccata composed by the scientist's brother, Michelangelo Galilei, transcribed from lute tablature. Chapter 1 of Part 1 investigates relevant historical threads extracted from the backdrop of Galileo's life, from reflections on the events that shape the musical program, to the selection and preparation of the period music composed by Galileo's brother. Chapter 2 discusses specific musical components of Galileo's Eyeglass, including form, musical quotations, motivic and thematic material, harmonic language, orchestration, and notation. Chapter 3 examines the principal philosophical themes behind the composition, including expressions of victory of a life well lived in spite of many obstacles. Part 2 contains the orchestral score.

Exomoons remain amongst the most elusive targets in observational astronomy. Nevertheless, these worlds stand to provide an unprecedented window into the formation and evolution of planetary systems. If the Solar System is any guide, we can expect exomoons will be geologically active and diverse, with the potential for hosting volatiles, atmospheres, and even life. Moreover, a thorough understanding of the population and occurrence rates of exomoons will help to place our own Solar System in a galactic context, speaking to the commonality of our own history. And though there are a variety of known pathways for moon formation, the discovery of exomoons may yet reveal heretofore unanticipated system architectures and defy easy explanation, thereby enriching our theoretical understanding of system formation. In this Dissertation I present a population study of exomoons in the Kepler data, finding an apparent dearth of Galilean-analog satellites orbiting planets between 0.1 and 1 AU. I then present evidence for a large exomoon orbiting Kepler-1625b -- potentially the first ever discovery of a transiting exomoon -- as suggested by a joint analysis of Kepler and Hubble Space Telescope data. The following chapter further investigates a number of alternative hypotheses relating to the candidate moon, though the conclusion that an exomoon best explains the data in hand remains unchanged. Finally, I present the results of an effort to identify candidate exomoon signals in the Kepler data by developing a convolutional neural network trained on O(10⁵) Kepler light curves injected with simulated planet and moon transit signals. The most promising exomoon candidates identified by the neural network are examined in detail, undergoing a full photodynamical model fit and Bayesian model selection. I conclude by discussing the outlook for the moon search, highlighting strategies for future work and myriad unanswered questions that should be pursued in the coming years.

This thesis contains the design, implementation, and testing of an original, small-scaled two degree-of-freedom telescope mount and a medium-scaled three degree-of-freedom telescope mount inspired by the six degree-of-freedom Stewart-Gough platform telescope mount. The end product is intended to achieve research-standard resolution of targeted sky coverage for binary star research. The scaled prototype was carried through concept design, manufacturing, software development, and testing. The mount software development and electronic design is applicable to a full-scale mount as the drivers have been designed to be easily adapted to different actuator configurations. It is recommended that this design be implemented into a telescope in the one to two meter range for economic practicality.

This study aims to investigate the similarities in precision and performance between a James WebbSpace Telescope mirror actuator, the part controlling the motion of the primary mirror segments,and two 3D printed replicas. The two replicas were made from the plastics PLA and PETGand based on the designs of Zachary Tong. The plastics were examined concurrently and theresults were compared with simulations in COMSOL. The 3D printed parts were assembled and theresulting replicas were put in motion by an Arduino driven stepper motor. The result showed thatthe replica made from PLA had an average precision of 40 nm and the replica made from PETGhad an average precision of 32 nm. Compared to the James Webb Space Telescope actuator, bothreplicas were approximately one order of magnitude less accurate. The COMSOL simulations gavesimilar results. In conclusion, the study shows that the choice of material matters. The performanceof the James Webb Space Telescope actuator was more accurately emulated by the replica madefrom PETG than by the one made from PLA.

No description available.

Jupiter's aurorae put on a permanent, ever-changing light show more than a thousand times brighter than the Earth's own aurorae. At ultraviolet wavelengths these aurorae are dominated by the ME: discontinuous ovals of curtain-like light partially encircling each of the planet's magnetic poles. The properties of these aurorae are a reflection of processes in Jupiter's magnetosphere, as the two are coupled together by currents flowing along magnetic field lines. By understanding auroral features in the ME, the vast Jovian magnetosphere's complex interactions with the planet can thus be better understood. The evolution of this energetic system has implications for Jupiter's present and past, as well as its place within the Solar System. While Jupiter's large-scale aurorae have been extensively studied, the properties, particularly motions, of small-scale auroral features represent a comparatively unexplored route to gain deeper understanding of this system. Here, the motions of these auroral features are characterized and related back to the physical processes in Jupiter's magnetosphere and ionosphere. First, a survey of auroral feature motions in Jupiter's ME is created based on Hubble Space Telescope observations. A dichotomy in auroral motion is found: features near dawn remain fixed in local time significantly more than features elsewhere. This finding gives context for Jupiter's dawn storms-- rare, enigmatic auroral phenomena noted for their fixedness, brightness, and appearance only at local dawn. Next, the ME is measured on smaller scales and compared with in-situ measurements of magnetospheric plasma flow from the Galileo spacecraft to estimate the magnetospheric and ionospheric properties associated with fixed auroral features. Finally, these properties are used to inform a self-consistent model of the currents generating the ME. Ionospheric conductance-- the ease with which currents flow through the ionosphere-- is varied to generate models which best match the auroral observations. Altogether, a coherent description of ME auroral features and their associated physical processes emerges. Increased conductance is found to correspond with both auroral emissions and the acceleration of magnetospheric plasma. The conductance, which is spatially variable but fixed in local time on average, is proposed to explain the motions of small-scale ultraviolet Jovian auroral forms.

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.