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The Global ETD Search service is a free service for researchers
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 11 to 20 of 20 (0.08 seconds)Spelling suggestions: "subject:"astronomical instruments"" "subject:"gastronomical instruments""
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Scientific controversy and the new astronomy : the intellectural and social contexts of the Hevelius-Hooke dispute /Saridakis, Voula. January 1993 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 126-132). Also available via the Internet.
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Scientific controversy and the new astronomy: the intellectual and social contexts of the Hevelius-Hooke disputeSaridakis, Voula 10 November 2009 (has links)
During the seventeenth century, science, and especially astronomy, underwent significant changes in which the emphasis on instrumentation shifted from a more qualitative approach to precise quantitative measurement. These changes were further encouraged by the formation of scientific societies, such as the Royal Society in London and the Royal Academy of Sciences in Paris, where members worked together as a collective to validate knowledge. Because members could freely dissent within the community, a prescribed behavior for participants in disputes was proposed, although seldom followed. Furthermore, disputes were not influenced by intellectual issues alone -- social factors also guided and influenced the course of controversies.
This study is an analysis of one scientific controversy in which the participants deviated from the prescribed code of behavior in scientific disputes, and, although the controversy was guided primarily by social factors, intellectual factors ultimately determined its outcome. In the Introduction, I discuss two sociological theses (Merton, Shapin and Schaffer) which are relevant to scientific controversies. In Chapter 1, I describe the changing nature of astronomy and instrumentation in the seventeenth century with special emphasis on micrometers and telescopic sights. In Chapter 2, I explore the nature of scientific controversy vis-à-vis the Royal Society, and two particular controversies which did not deviate from the expected rules of behavior. A descriptive account of the Hevelius-Hooke dispute follows in Chapter 3, and in Chapter 4, I provide concluding remarks on the dispute. Finally, in the Conclusion, I discuss the intellectual and social contexts of the Hevelius-Hooke dispute. / Master of Science
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Observations of starburst galaxies science and supporting technology /Laag, Edward Aric. January 2009 (has links)
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.
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A universe of sky and snow: site-testing for optical astronomy at Dome C, AntarcticaKenyon, Suzanne Laura, Physics, Faculty of Science, UNSW January 2007 (has links)
The unique advantages for astronomy on the Antarctic plateau are now well established. In particular, Dome C, Antarctica is potentially one of the best new sites for optical, infrared and sub-millimeter astronomy, presenting the opportunity to build unique astronomical instruments. Located high on the Antarctic plateau, Dome C offers low wind, clear skies, and negligible precipitation. This thesis addresses three additional properties of the site relevant to optical astronomy-sky brightness, atmospheric extinction and optical turbulence. The sky at an optical astronomy site must be dark, and the atmosphere very clean with minimal light extinction. At present little is known from an astronomer's perspective about the optical sky brightness and atmospheric extinction at most Antarctic sites. The high latitude of Dome C means that the Sun spends a relatively small amount of time far below the horizon, implying longer periods of astronomical twilight and less optical dark time than other sites, especially those close to the equator. We review the contributions to sky brightness at high-latitude sites, and calculate the amount of usable dark time at Dome C. We also explore the implications of the limited sky coverage of high-latitude sites, and review optical extinction data from the South Pole. A proposal to extend the amount of usable dark time through the use of polarising filters is examined, and we present the design and calibration of an instrument (called Nigel) to measure the brightness, spectrum and temporal characteristics of the twilight and night sky. The atmospheric turbulence profile above an astronomical site limits the achievable resolution and sensitivity of a telescope. The atmospheric conditions above high plateau Antarctic sites are different to temperate sites; the boundary layer of turbulence is confined very close to the surface, and the upper atmosphere turbulence very weak. We present the first winter-time turbulence profiles of the atmosphere above Dome C, and characterise the site in terms of the achievable precision for photometry and astrometry, and the isoplanatic angle and coherence time for the adaptive optics.
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Automation of the acquisition system of the 1,9 m telescope for the charge coupled device (CCD) cameraCarter, DB January 1988 (has links)
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.
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"Strange machines" from the West: European curiosities at the Qing imperial courts, 1644-1796Braun, Stephanie Eva. January 2011 (has links)
published_or_final_version / Fine Arts / Master / Master of Philosophy
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Designing and implementing a new pulsar timer for the Hartebeesthoek Radio Astronomy ObservatoryYouthed, Andrew David January 2008 (has links)
This thesis outlines the design and implementation of a single channel, dual polarization pulsar timing instrument for the Hartebeesthoek Radio Astronomy Observatory (HartRAO). The new timer is designed to be an improved, temporary replacement for the existing device which has been in operation for over 20 years. The existing device is no longer reliable and is di±cult to maintain. The new pulsar timer is designed to provide improved functional- ity, higher sampling speed, greater pulse resolution, more °exibility and easier maintenance over the existing device. The new device is also designed to keeping changes to the observation system to a minimum until a full de-dispersion timer can be implemented at theobservatory. The design makes use of an 8-bit Reduced Instruction Set Computer (RISC) micro-processor with external Random Access Memory (RAM). The instrument includes an IEEE-488 subsystem for interfacing the pulsar timer to the observation computer system. The microcontroller software is written in assembler code to ensure optimal loop execution speed and deterministic code execution for the system. The design path is discussed and problems encountered during the design process are highlighted. Final testing of the new instrument indicates an improvement in the sam- pling rate of 13.6 times and a significant reduction in 60Hz interference over the existing instrument.
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Temperature dependence of the HartRAO pointing modelCopley, Charles Judd January 2008 (has links)
This thesis investigates control aspects of the Hartebeeshoek Radio Astronomy Observatory (HartRAO) antenna. The installation of a new 22 GHz receiver has required the pointing accuracy to be improved to less than 4 mdeg. The effect of thermal conditions on the the HartRAO antenna pointing offset is investigated using a variety of modelling techniques including simple geometric modelling, neural networks and Principal Component Analysis (PCA). Convincing results were obtained for the Declination pointing offset, where applying certain model predictions to observations resulted in an improvement in Declination pointing offset from 5.5 mdeg to 3.2 mdeg (≈50%). The Right Ascension pointing model was considerably less convincing with an improvement of approximately from 5.5 mdeg to 4.5 mdeg (≈20%) in the Right Ascension pointing offset. The Declination pointing offset can be modelled sufficiently well to reduce the pointing offset to less than 4 mdeg, however further investigation of the underlying causes is required for the Right Ascension pointing offset.
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Design of a flexure mount for optics in dynamic and cryogenic environmentsPollard, Lloyd Wayne, 1936- January 1988 (has links)
The design of the flexure mount recently submitted to NASA Ames for the structural support of the primary mirror of the Space Infrared Telescope Facility (SIRTF) is presented. The flexure system must passively accommodate the differential thermal contraction between the glass mirror and the aluminum structure of the telescope during cryogenic cooldown. Further, it must support the one meter diameter, 116 kilogram (258 pound) primary mirror during a severe launch to orbit. Procedures used to establish the required radial compliance using computer programs NASTRAN and FRINGE are discussed. The parametric design program developed to study early concepts is presented. Methods of combining modal responses resulting from a displacement response spectrum analysis are discussed, and a combination scheme called MRSS, Modified Root of Sum of Squares, is presented. Modal combination schemes using MRSS, SRSS, and ABS are compared to the results of a Modal Frequency Response analysis.
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Johann Friedrich von Uffenbach. Sammler – Stifter – Wissenschaftler / Johann Friedrich von Uffenbach. Collector - Donor - ScientistMeyerhöfer, Dietrich 28 January 2020 (has links)
No description available.
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