Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: D.E. Winget. Vita. Includes bibliographical references. Also available from UMI.

Thesis (M. Arch.)--University of Hong Kong, 1994. / Includes special study report entitled: Cosmology and its relations to architecture. Includes bibliographical references. Also available in print.

Thesis (Ph. D.)--University of Canterbury, 2001. / Typescript (photocopy). Includes bibliographical references (p. [215]-225). Also available via the World Wide Web.

High resolution imaging and spectroscopy are invaluable tools for extragalactic astronomy. Galaxies with redshifts of 1 or more subtend a very small angle on the sky—typically, only about an arcsecond. Unfortunately, this is also approximately the angular resolution achieved with a ground-based telescope regardless of its aperture. Atmospheric turbulence ruins the image before it reaches the telescope but the emerging technology of adaptive optics (AO) gives the observer the possibility, within limitations, of correcting for these effects. This is the case for instruments such as the Canada-France-Hawaii Telescope (CFHT) Adaptive Optics Bonnette (AOB) and the Gemini North Telescope (Gemini) Altitude-Conjugate Adaptive Optics for the Infrared (Altair) systems. The alternative is to rise above the limitations of the atmosphere entirely and put the telescope in space, for example, the Hubble Space Telescope (HST) and its successor, the Next-Generation Space Telescope (NGST). I discuss several techniques that help overcome the limitations of AO observations with existing instruments in order to make them more comparable to imaging from space. For example, effective dithering and flat-fielding techniques as well as methods to determine the effect of the instrument on the image of, say, a galaxy. The implementation of these techniques as a software package called AOTOOLS is discussed. I also discuss computer simulations of AO systems, notably the Gemini Altair instrument, in order to understand and improve them. I apply my AO image processing techniques to observations of high-redshift radio galaxies (HzRGS) with the CFHT AOB and report on deep imaging in near-infrared (NIR) bands of 6 HzRGs in the redshift range 1.1 ≤ z ≤ 3.8. The NIR is probing the restframe visible light—mature stellar populations—at these redshifts. The radio galaxy is resolved in all of these observations and its ‘clumpier’ appearance at higher redshift leads to the main result—although the sample is very small—that these galaxy environments are undergoing mergers at high redshift. Finally, I look to the future of high resolution observations and discuss simulations of imaging and spectroscopy with the NGST. The computer software NGST VI/MOS is a ‘virtual reality’ simulator of the NGST observatory providing the user with the opportunity to test real observing campaigns. / Graduate

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.

A new version of Reticent, a command language to manipulate digital spectroscopic data, has been developed and applied to the analysis of time series of spectra. Observations of the Ca II 8498A and 8542A line profiles of Delta Delphini indicate variations in the radial velocity with an amplitude of about 8 kms⁻¹. The radial velocity variations were accompanied by variations in the depth of the line profiles. Observations of the H alpha emission line profile of Nova Cygni 1978 (V1668 Cygni) indicate that the continuum level declined by 0.46 magnitude between JD2443769.9 and JD2443770.8. The P. Cygni profile of the diffuse enhanced system appeared between JD2443769.9 and JD2443770.7. The absorption feature of the P. Cygni profile had a velocity of -960 kms⁻¹. Variations in the continuum level with an amplitude of 0.04; magnitude were detected between JD2443770.70 and JD2443770.97. The variations in the continuum level were accompanied by variations in the shape of the H alpha emission line profile. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

Measuring periodic changes in the line-of-sight velocities of stars via spectroscopy (the “radial velocity technique”) is a well-established method to detect planets orbiting stars other than the Sun. As those distant stars orbit their system’s center of mass the radial velocity technique confirms that companions exist and allows for the measurement of fundamental parameters: companion masses, orbital characteristics, and, in some cases, aspects of atmospheric chemistry. Until recently Doppler spectrometers have been limited to detecting radial velocity signals of larger than one meter-per-second, a constraint that significantly hinders our discovery and characterization of small rocky worlds similar to our own. This is the motivation for developing instruments sensitive to extremely precise radial velocities (EPRVs, ??? < 1ms−1). This dissertation describes critical aspects of the development of one such spectrometer: the Palomar Radial Velocity Instrument (PARVI).Chapter 2 presents the characterization of the fine-guiding camera used in the fiber injection unit that couples light from Palomar’s extreme adaptive optics to the spectrograph’s single-mode fiber feed. Chapter 3 describes the data acquisition and data reduction pipelines for PARVI. It includes the methodology for acquiring data with a Teledyne H2RG array, the description of the wavelength calibration using a laser frequency comb, and the process for reducing the 2D echellogram down to a 1D spectrum. Chapter 4 reveals the discovery of a new and significant, polarization-dependent, instrument noise and a warning for those considering using single-mode fibers for high resolution spectroscopy. Chapter 5 contains the first results from PARVI commissioning data. This includes the detection of the Rossiter-Mclaughlin signal of the transiting planet HD 189733 b, and presence of water and carbon monoxide in the atmosphere of HD 189733 b via transmission spectroscopy.

Following the foundation of aberration theory for rotationally symmetric optical systems established by Seidel, Schwarzschild, Burch, Conrady, Buchdahl, and in its most useful form H.H. Hopkins, Shack, Buchroeder, Thompson, and Rogers developed a vectorial form of the wave aberration theory that enables addressing optical systems without symmetry. In this research, a vectorial theory is utilized and extended for the alignment of two- and three-mirror astronomical telescopes, including the effects of pointing changes and astigmatic figure errors. Importantly, it is demonstrated that the vectorial form of aberration theory, also referred to as nodal aberration theory, not only provides valuable insights but also facilitates a quantitative description of the aberrations in optical systems without symmetry. Specifically, nodal aberration theory has been utilized to establish key insights into the aberration field response of astronomical telescopes to misalignments. Important nodal properties have been derived and discussed and the theoretical predictions have been validated with optical design software. It has been demonstrated that the removal of on-axis coma in some of the most common astronomical telescopes in use today directly leads to a constraint for one of the nodes for astigmatism to be located at the field center, which is exactly true for Cassegrain or Gregorian telescopes, and approximately true for Ritchey-Chretien (or aplanatic Gregorian) telescopes. These observations led to important conclusions concerning the alignment of astronomical telescopes. First, the correction of these telescopes on-axis for zero coma removes all misalignment induced aberrations only on-axis. Secondly, given that the image quality at the field center remains stigmatic in the presence of misalignments, for these telescopes non-zero astigmatism measured at the field-center directly reveals astigmatic mirror figure errors. Importantly, the effects of misalignments and astigmatic figure error can be clearly distinguished if present in combination, even in the presence of significant boresight errors. Having the possibility to clearly distinguish between misalignment and astigmatic mirror figure error provides an important prerequisite for the optimal operation of active/adaptive optics systems that are becoming standard in observatory class telescopes. Subsequent work on TMA telescopes revealed that even though TMAs are limited by fifth order aberrations in their nominal alignment state, third order nodal aberration theory provides accurate image quality predictions for misalignments and astigmatic figure (third order) effects in these optical systems. It has been demonstrated for the first time that analytical expressions can be devised that describe the characteristic misalignment induced aberration fields of any TMA telescope, leading to two main image quality degrading aberrations, field-constant coma and field-linear, field-asymmetric astigmatism. These new insights can be strategically leveraged in the development of alignment strategies for TMAs. The final part of this work analyzed how third and fifth order nodal aberration fields can be utilized in the alignment of wide-angle telescopes, with the specific example of the Large Synoptic Survey Telescope (LSST). In cooperation with the National Optical Astronomy Observatory (NOAO) an alignment strategy has been developed for the LSST (without camera) to expedite the commissioning of the telescope, providing for the first time analytical expressions for the computation of misalignment parameters in three-mirror telescopes, taking into account fabrication tolerances for the alignment of the tertiary mirror on the primary mirror substrate. Even though the discussion has been focused primarily on alignment strategies of astronomical telescopes, the methods and algorithms developed in this work can be equally applied to any imaging system.