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A real-time discrete-event simulation model is built to emulate the functional operations of the Thaw telescope of the Allegheny Observatory and its attached scientific instrument. The OASIS software system is used to communicate with the simulation model. This simulation model, written in Ada, consists of three major parts. The Command Receiver and the Data Transmitter are software written to service the incoming telecommands and outgoing telemetry, the Command Processor is the actual simulator itself consisting of a Command Retriever, a Scanner, a Parser, a Command Interpreter, and the actual Thaw telescope simulation. The motivation for our simulation model and discussion of design issues are presented in chapters 1 and 2. The details of the model are documented in chapters 3, 4, and 5. The final two chapters include examples, questions, thoughts for future work, and conclusions.

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The Pyramid Sensor (PS) is a promising wavefront sensor (WFS) for astronomical adaptive optics (AO) due to its potential to increase the number of accessible scientific targets by more efficiently using guide star (GS) photons. This so-called magnitude gain, as well as the key role played by the PS in several novel multi-reference wavefront sensing schemes have generated intense interest in the device. The diffraction based theory of PS and the underlying optical shop test, the Foucault knife-edge test, is reviewed. The theory is applied to calculate the magnitude gain. The impact of the magnitude gain on the number of galaxies accessible to observation with classical A0 on a TMT sized telescope for the Virgo Cluster Catalogue is assessed via simulations. Additional simulation results are shown to elucidate the impact of various parameters of the pyramidal prism on the magnitude gain. The results of experiments conducted in the UVIC A0 lab with a prototype Id PS are discussed. The Id PS uses a novel optical element called a holographic diffuser to linearize the response of the PS to wavefront tilt. The results of calibrating the sensor are given as well as caveats to the use of such a device. The results of using the Id PS to measure a static aberration as well as spatial and temporal characterization of turbulence produced by the UVIC A0 lab's Hot-Air Turbulence Generator are given.

This is an investigation of the proposed ‘Square Kilometer Array’ (SKA) for the next generation radio telescope. A parallel plate system with a circular reflector has been investigated for SKA to achieve wideband performance and beam scanning ability, in particular the theoretical analysis of the fields in the parallel plate structure using a combination of Finite Difference Time Domain method and Physical Optics. This study builds on earlier work, explores the possible limits of extension and develops an analysis of the device, which will allow all possible configurations to be simulated. It is anticipated that the final scanning arrangement will consist of at least a double reflector system, possibly with some re-configurability, where the parallel plates will have two 180 degree bends with the output being some form of directly radiating aperture. Results were obtained for a Re-configurable Monopole, where diodes are used as switches to physically vary the length of the antenna element and hence increase the bandwidth of the antenna. Re-configurable reflectors were also investigated and Geometrical Optics was used for shaping a dual-reflector Cassegrain system for beam scanning. All of these methods have produced satisfactory practical and analytical results / Doctor of Philosophy (PhD) Electrical Engineering

The horn plays an elemental role in the make up of a radio-telescope. The focus of this research is on one particular type of horn – the diagonal horn. An analysis of the diagonal horn is made using the Fourier method. The analysis begins from Maxwell’s equations, as the basic building block, and describes the steps involved in developing the radiation pattern. Based on the theory, a program was written that produces the theoretical graphs referred to throughout the thesis. A diagonal horn was manufactured and the radiation patterns were measured. A comparison of these measured patterns is made against the theoretically generated patterns. Further research was carried out to demonstrate the effects on the radiation patterns when the horn is fitted with a dielectric plug. This practice may enhance the directivity of the horn at the cost of introducing new losses / Master of Engineering (Hons)

Thesis (M.S.)--University of Kentucky, 2001. / Title from document title page. Document formatted into pages; contains x, 87 p. : ill. Includes abstract. Includes bibliographical references (p. 83-86).

Infrared astronomical observations have been severely limited by the radiation emitted by the aluminum coated surfaces of telescope mirrors. Hence, the reduction of emissivity with retention of coating durability for telescope optics is now an important area of study essential for the improvement of infrared astronomical observations. To avoid the considerable effort that a search for a new material superior to aluminum would demand with uncertain outcome, only existing materials were investigated and silver with a protective dielectric layer was thought to be a possible solution. Experiments at Kitt Peak National Observatory showed that the optical performance of a silver coating is better than aluminum in the infrared and visible regions, but even with a sapphire overcoating the silver proved to have such poor environmental resistence that an experimental mirror had to be recoated after just ten months in service. Thus, the improvement of the durability of a silver-based high reflectance coating becomes a key issue that has to be solved for such a coating to be selected for infrared astronomy. Furthermore, most telescopes are used also in the ultraviolet and so any successful coating would need to reflect well in this region. Silver is poor also in this respect. In this dissertation, we describe the development of a silver-based high reflectance coating that can withstand the humidity and pollution common in the open air and which has good ultraviolet, visible, and infrared performance. The successful design incorporates a silver reflective layer with a copper underlayer and a stack of dielectric overlayers. Prototypes of the candidate coating have been deposited on two-inch glass slides and tested in a controlled environmental chamber and under true operating conditions on Kitt Peak in Arizona. The improved durability, partly due to the copper underlayer, has been investigated with analytical techniques, including Rutherford backscattering. The results showed that the protection of the silver is due not only to the dielectric stack and the copper beneath the layer, but also to a small amount of copper that appears on the outer surface of the silver layer. This surface copper may result from diffusion through the silver layer after the coating deposition, or may be a consequence of a process during film growth. Whatever the reason, the candidate coatings have better optical performance and improved durability so they are recommended for use on large telescope mirrors for astronomical observations in the near ultraviolet, visible, and infrared spectral regions.

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