Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"Ground based telescopes"”.
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Dynamics of multi-body space interferometers including reaction wheel gyroscopic stiffening effects : structurally connected and electromagnetic formation of flying architectures
Space telescopes have the potential to revolutionize astronomy and our search for life-supporting planets beyond our Solar System. Free of atmospheric distortions, they are able to provide a much "clearer" view of the universe than ground-based telescopes. A developing technology that appears …
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Long exposure point spread function estimation from solar adaptive optics loop data
… to obtain diffraction-limited observations from ground-based telescopes. However, the AG correction is only partial and post-processing with a good estimate of the point spread function (PSF) is required. PSF estimates are impossible to measure directly during solar observations due to the lack …
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Multi-Conjugate Adaptive Optics for LINC-NIRVANA : Laboratory Tests of a Ground-Layer Adaptive Optics System and Virtical Turbulence Measurements at Mt. Graham
… atmosphere severely limits the image quality of ground-based telescopes. With the technique of Adaptive Optics, the induced distortions of the light can be measured and corrected in real-time, regaining nearly diffraction-limited performance. Unfortunately, when using a single guide star to …
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Lucky exposures: diffraction limited astronomical imaging through the atmosphere
… of astronomical imaging from large optical telescopes is usually limited by the blurring effects of refractive index fluctuations in the Earth’s atmosphere. By taking a large number of short exposure images through the atmosphere, and then selecting, re-centring and co-adding the best images …
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Reconstruction of stellar images from correlations
… astronomical image data observed by ground-based telescopes is addressed. The observations are seriously degraded by atmospheric turbulence as well as corrupted by photon noise, detection noise and background noise. An approach for the reconstruction of the unknown object using the …
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High Contrast Imaging: Exoplanet and Low Stellar Mass Populations
… a lower resolution than 8 m class AO-assisted ground-based telescopes, which have been used for constraining the frequency of 0.5 − 13 MJ planets at separations of 10 − 102 AU, its exquisite infrared sensitivity provides the ability to place unmatched constraints on the planetary populations at …
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Data-driven Approaches to Stellar Variability Detection and Characterisation
… data, such as photometric light curves from ground-based telescopes. I demonstrated that this algorithm accurately estimated the standard ACF, even for poorly sampled astrophysical data, and produced accurate rotation periods that agreed with more complex and computationally expensive models. …
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High resolution solar observations from first principles to applications
… are more closely linked with the solar telescopes that they serve than in past. In principle, the quest for high-resolution observations already starts with the selection of the observatory site. The site survey of the Advanced Technology Solar Telescope (ATST) under the stewardship of …
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MCAO for Extremely Large Telescopes: the cases of LBT and E-ELT
… the current and of the future generation large ground-based telescopes (diameters in the 8-40 m range). The subject of this PhD Thesis is embedded in this context. Two MCAO systems, in dierent realization phases, are addressed in this Thesis: NIRVANA, the 'double' MCAO system designed for one of …
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Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory
… with Global Positioning devices and optical telescopes, ensure the fast-cadence capture of these events with microsecond timing accuracy. This high-time resolution observing in combination with the relative speed of the star and the occulting body ensures accurate results with resolutions …
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Reverberation Mapping of Supermassive Black Holes using Machine Learning
… and apply frequency-domain timing techniques based on Gaussian Process (GP) regression to study AGN reverberation across X-ray and UVOIR regimes. By modeling the empirical variability of AGN light curves with GPs, I interpolate onto an evenly sampled time grid, enabling robust estimation of …
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New Advances in Exoplanet Spectroscopy from Space and Ground
… wavelength coverage in the infrared, while large ground-based telescopes are facilitating high-resolution spectroscopy in the optical and near-infrared. This surge of high-quality data is enabling precise atmospheric characterisation across a diverse range of exoplanets, from hot Jupiters to …
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Molecular Characterisation of Exoplanetary Atmospheres using High-Resolution Transmission Spectroscopy
… years, high-resolution spectrographs on large ground-based telescopes are powerful tools with significant scientific potential. However, ground-based observations are complicated and limited by the Earth’s own atmospheric absorption. We here set out to advance high-resolution transmission …
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Detecting and understanding extragalactic Lyman α emission using 3D spectroscopy
… z~3, where Lyα is easily accessible with ground-based telescopes. However, star-forming galaxies do not show these expected Lyα fluxes. Primarily this is a consequence of the high-absorption cross-section of neutral hydrogen for Lyα photons σ ~ -14 dex (cm²). Therefore, in typical …