ISIS is a program that specializes in detecting variable stars within clusters, both open and globular. ISIS has historically been used in surveys searching for variable stars. However, recent work has identified new uses for ISIS, such as the detection of exoplanet transits in clusters of stars. This thesis will evaluate ISIS, both how the program functions and for which objects it is most efficient and appropriate. I examined five clusters: three open, and two globular, for one night surveys. With this survey, I identified twenty-five variable stars. Twenty-two variables were previously known, and three variable stars were previously undiscovered. In total, from my short one night surveys, I confirmed twenty-five previously known variable stars and four unknown variable stars. Furthermore, ISIS has detected several δ Scuti stars whose amplitude of variation is on par with an exoplanet transit. These data suggest that ISIS can be used for the detection of exoplanet transits. / Department of Physics and Astronomy

QC 351 A7 no. 20 / The control system described in this thesis was designed to automatically guide the position of photographic plates during long exposures of astronomical objects. The system senses the position of the guide star which is being used as a position reference, and moves the photographic plate in two orthogonal directions in order to maintain a constant position of the image of the astronomical object on the photographic plate. The system was designed to have a bandwidth of 35 radians per second in order to track the worst case image excursions due to atmospheric turbulence and telescope motion. The closed loop transient response of the system was determined from considerations of final image resolution of the photographic plate. Due to the necessity of guiding on stars of unknown brightness the system incorporated an automatic gain control loop within the forward control loop and was made unconditionally stable by high order feedback. In operation on the Steward Observatory telescopes, the system has made a significant increase in photographic plate resolution over manually guided plates.

Magister Artium - MA / This study explores the nuances around gendered dynamics, attitudes, ideologies, values and knowledge that exist within astronomy and astrophysics institutions paying specific attention to the South African Astronomical Observatory (SAAO) as study site. This study investigated implicit and explicit ways in which SAAO spaces and practices are gendered and hierarchized, and the extent to which 'astronomy as a specific discipline within science' remains highly masculinized. By focusing on studies on power, feminist critiques of science and institutional culture in other South African sectors, especially higher education, the study deconstructs a field that has been relatively neglected in South African feminist studies of gendered institutional culture. This thesis makes use of feminist qualitative methodological approaches and fuses mixed methods to collect data. The use of participant observation enabled a broader understanding of the context and to gain an understanding of how gendered, classed and raced subjects construct and navigate social meanings in the hierarchized and symbolically marked space of the SAAO. / National Research Foundation (NRF)

Thesis. 1979. M.Arch--Massachusetts Institute of Technology. Dept. of Architecture. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / by Frank C. Miller. / M.Arch

Charge-Coupled-Device (CCD) cameras have opened a new world in astronomy and other related sciences with their high quantum efficiency, stability, linearity, and easy handling. Nevertheless, there is still noise in raw CCD images and even more noise is added through the image calibration process. This makes it essential to know exactly how the calibration process impacts the noise level in the image. The properties and characteristics of the calibration frames were explored. This was done for bias frames, dark frames and flat-field frames at different temperatures and for different exposure times. At first, it seemed advantageous to scale down a dark frame from a high temperature to the temperature at which the image is taken. However, the different pixel populations have different doubling temperatures. Although the main population could be scaled down accurately, the hot pixel populations could not. A global doubling temperature cannot be used to scale down dark frames taken at one temperature to calibrate the image taken at another temperature. It was discovered that the dark count increased if the chip was exposed to light prior to measurements of the dark count. This increase, denoted as dark offset, is dependent on the time and intensity of the prior exposure of the chip to light. The dark offset decayes with a characteristic time constant of 50 seconds. The cause might be due to storage effects within chip. It was found that the standard procedures for image calibration did not always generate the best and fastest way to process an image with a high signal-to-noise ratio. This was shown for both master dark frames and master flat-field frames. In a real world example, possible night sessions using master frame calibration are explained. Three sessions are discussed in detail concerning the trade-offs in imaging time, memory requirements, calibration time, and noise level. An efficient method for obtaining a noise map of an image was developed, i.e., a method for determining how accurate single pixel values are, by approximating the noise in several different cases.

The thesis' primary function was the period determination of k Bootis, and S Scuti Variable, through long time-base UBV photoelectric photometry. Data was analyzed using Barning's method, a Fourier technique in searching for the primary and beat periods within the range 0.0486 to 0.0826 days and 13 to 19 days respectively. The study's secondary function was the identification of overtones and the acquisition of any other information concerning this star.Ambiguity resulting from the period determinations of Millis (1966) and Desikachary et al. (1971) was tentatively resolved; the most accurate determination from this investigation gives a period of 0.07361 days and a (m of 0.05 magnitude. A beat period of 13.32 days with a o m of 0.088 magnitude was found which widely differs from the 16-day beat suggested by the Desikachary group. Due to noise problems, secondary frequencies could not be soundly identified, though the Fourier "spectra" indicated their existence. However, this study when combined with that of Desikachary et al. supports the hypothesis that K Bootis might have an undiscovered very close companion in addition to its "wide" binary component. This close binary nature may be typical of one type of δ Scuti variable.Ball State UniversityMuncie, IN 47306

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 16, 2010). Includes bibliographical references. Also issued in print.

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

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