Relevant bibliographies by topics / Coronagraphie / Dissertations / Theses
To see the other types of publications on this topic, follow the link: Coronagraphie.

Dissertations / Theses on the topic 'Coronagraphie'

Author: Grafiati
Published: 7 July 2024
Last updated: 31 July 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 40 dissertations / theses for your research on the topic 'Coronagraphie.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

SCHMITTE, RIVEZ ANNICK. "Interets du doppler des membres inferieurs avant coronagraphie." Reims, 1992. http://www.theses.fr/1992REIMM067.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Alagao, Mary Angelie. "Characterization and optimization of the Evanescent Wave Coronagraph." Electronic Thesis or Diss., Saint-Etienne, 2023. http://www.theses.fr/2023STET0060.

Full text
Abstract:
L’imagerie directe des exoplanètes reste difficile en raison du contraste élevé et de la faible séparation angulaire entre l'étoile et la planète. Cela nécessite de supprimer l'éblouissement dû à l'étoile et de s'assurer que la lumière faible de la planète n'est pas noyée au milieu de divers bruits. La détection dépend de la maturité des techniques et des algorithmes utilisés, tout en tenant compte des compromis importants sur le contraste brut, la résolution angulaire et la transmission. L'une de ses composantes clés est l'utilisation de coronagraphes - des instruments ayant pour seul but de
APA, Harvard, Vancouver, ISO, and other styles
3

Chipman, Russell A. "Challenges in coronagraph optical design." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627190.

Full text
Abstract:
The point spread function (PSF) for astronomical telescopes and instruments depends not only on geometric aberrations and scalar wave diffraction, but also on the apodization and wavefront errors introduced by coatings on reflecting and transmitting surfaces within the optical system. Geometrical ray tracing provides incomplete image simulations for exoplanet coronagraphs with the goal of resolving planets with a brightness less than 10<^>-9 of their star located within 3 Airy disk radii. The Polaris-M polarization analysis program calculates uncorrected coating polarization aberrations couple
APA, Harvard, Vancouver, ISO, and other styles
4

Xin, Yeyuan(Yeyuan Yinzi). "Coronagraphic data post-processing using projections on instrumental modes." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127114.

Full text
Abstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, May, 2020<br>Cataloged from the official PDF of thesis.<br>Includes bibliographical references (pages 71-76).<br>High contrast astronomy has yielded the direct observations of over a dozen exoplanets and a multitude of brown dwarfs and circumstellar disks. Despite advances in coronagraphy and wavefront control, high contrast observations are still plagued by residual wavefront aberrations. Post-processing techniques can provide an additional boost in separating residual aberrations from an astrophy
APA, Harvard, Vancouver, ISO, and other styles
5

Pueyo, Laurent, Neil Zimmerman, Matthew Bolcar, et al. "The LUVOIR architecture ``A'' coronagraph instrument." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/626292.

Full text
Abstract:
In preparation for the Astro 2020 Decadal Survey NASA has commissioned the study four flagship missions spanning to a wide range of observable wavelengths: the Origins Space Telescope (OST, formerly the Far-Infrared Surveyor), Lynx (formerly the X-ray Surveyor), the Large UV/Optical/Infrared Surveyor (LUVOIR) and the Habitable Exoplanet Imager (HabEx). One of the key scientific objectives of the latter two is the detection and characterization of the earth-like planets around nearby stars using the direct imaging technique (along with a broad range of investigations regarding the architecture
APA, Harvard, Vancouver, ISO, and other styles
6

Thompson, Samantha Jayne. "OSCA, an Optimised Stellar Coronagraph for Adaptive optics." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1338360/.

Full text
Abstract:
Described here is the design, manufacturing, testing and commissioning of a coronagraph facility for the 4.2 metre William Herschel Telescope (WHT) and its adaptive optics system (NAOMI). The use of the NAOMI adaptive optics system gives an improved image resolution of ~ 0.15 arcseconds at a wavelength of 2.2μm. This enables the Optimised Stellar Coronagraph for Adaptive optics (OSCA) to null stellar light with smaller occulting masks and thus allows regions closer to bright astronomical objects to be imaged. OSCA is a fully deployable instrument which when in use leaves the focus of the NAOMI
APA, Harvard, Vancouver, ISO, and other styles
7

Chipman, Russell A. "Image formation in coronagraphs due to mirror polarization aberrations." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627180.

Full text
Abstract:
The PSF for astronomical telescopes and instruments depends not only on geometric wavefront aberrations, but also on those polarization aberrations from the polarization properties of reflecting and transmitting surfaces. The image plane irradiance distribution is the linear superposition of four PSF images: one for each of the two orthogonal polarizations and one for each of two cross-coupled polarization terms.
APA, Harvard, Vancouver, ISO, and other styles
8

Mawet, D., P. Wizinowich, R. Dekany, et al. "Keck Planet Imager and Characterizer: concept and phased implementation." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622026.

Full text
Abstract:
The Keck Planet Imager and Characterizer (KPIC) is a cost-effective upgrade path to the W.M. Keck observatory (WMKO) adaptive optics (AO) system, building on the lessons learned from first and second-generation extreme AO (ExA0) coronagraphs. KPIC will explore new scientific niches in exoplanet science, while maturing critical technologies and systems for future ground-based (TMT, FELT, GMT) and space-based planet imagers (HabEx, LUVOIR). The advent of fast low-noise IR cameras (IR-APD, MKIDS, electron injectors), the rapid maturing of efficient wavefront sensing (WFS) techniques (Pyramid, Zer
APA, Harvard, Vancouver, ISO, and other styles
9

Knight, Justin M., John Brewer, Ryan Hamilton, Olivier Guyon, Thomas D. Milster, and Karen Ward. "Design, fabrication, and testing of stellar coronagraphs for exoplanet imaging." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627078.

Full text
Abstract:
Complex-mask coronagraphs destructively interfere unwanted starlight with itself to enable direct imaging of exoplanets. This is accomplished using a focal plane mask (FPM); a FPM can be a simple occulter mask, or in the case of a complex-mask, is a multi-zoned device designed to phase-shift starlight over multiple wavelengths to create a deep achromatic null in the stellar point spread function. Creating these masks requires microfabrication techniques, yet many such methods remain largely unexplored in this context. We explore methods of fabrication of complex FPMs for a Phased-Induced Ampli
APA, Harvard, Vancouver, ISO, and other styles
10

Martinache, Frantz, Nemanja Jovanovic, and Olivier Guyon. "Subaru Coronagraphic eXtreme Adaptive Optics: on-sky performance of the asymmetric pupil Fourier wavefront sensor." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622025.

Full text
Abstract:
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument relies on a technique known as the asymmetric pupil Fourier wavefront sensor (APF-WFS) to compensate for the non-common path error that affects the performance of high contrast imaging instruments. The APF-WFS is a powerful tool that senses the wavefront at the level of the science detector, and leads to unbiased wavefront estimates. This paper presents the latest status, linearity properties and reports on the on-sky performance of this sensor, as it is implemented on SCExAO, used to control low-order Zernike modes in a clos
APA, Harvard, Vancouver, ISO, and other styles
11

Newman, Kevin, Dan Sirbu, Ruslan Belikov, and Olivier Guyon. "Development of PIAA Complex Mask Coronagraphs for large aperture ground-based telescopes." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622426.

Full text
Abstract:
The Phase Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) is an architecture for directly observing extrasolar planets, and can achieve performance near the theoretical limits for any direct-detection instrument. The PIAACMC architecture includes aspheric PIAA optics, and a complex phase-shifting focal plane mask that provides a pi phase shift to a portion of the on-axis starlight. The phase-shifted starlight is forced to interfere destructively with the un-shifted starlight, causing the starlight to be eliminated, and allowing a region for high-contrast imaging near the star.
APA, Harvard, Vancouver, ISO, and other styles
12

Martinez, Patrice. "Coronagraphs characterization for high-contrast imaging in the context of extremely large telescopes." Paris 7, 2008. http://www.theses.fr/2008PA077208.

Full text
Abstract:
Cette thèse s'inscrit dans le contexte de la détection directe de planètes extra-solaires avec les futures très grand télescopes au sol (30 à 42 mètres de diamètre). Les contrastes requis pour une telle détection nécessitent l'utilisation de système d'optique adaptative pour corriger les effets de la turbulence atmosphérique et de coronographes stellaires pour atténuer le flux de l'étoile dans lequel le signal de la planète est noyé. Le but de cette étude est donc d'optimiser, de comparer et de sélectionner les concepts de coronographes stellaires les plus adaptés aux contraintes imposées par
APA, Harvard, Vancouver, ISO, and other styles
13

Absil, Olivier, Dimitri Mawet, Mikael Karlsson, et al. "Three years of harvest with the vector vortex coronagraph in the thermal infrared." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622801.

Full text
Abstract:
For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 to 13 pm). Our AGPMs were first installed on VLT/NACO and VLT/VISIR in 2012, followed by LBT/LMIRCam in 2013 and Keck/NIRC2 in 2015. In this paper, we review the development, commissioning, on-sky performance, and early scientific results of these new coronagraphic modes and report on the lessons learned. We conclude with perspectives for future d
APA, Harvard, Vancouver, ISO, and other styles
14

Bush, Nathan L. "The impact of radiation damage on electron multiplying CCD technology for the WFIRST coronagraph." Thesis, Open University, 2018. http://oro.open.ac.uk/55053/.

Full text
Abstract:
This thesis follows an investigation into the effects of radiation damage on the e2v CCD201-20; the detector baselined for use in the WFIRST coronagraph imaging and spectroscopy camera systems (hereafter, WFIRST CGI). The CCD201 is an EM-CCD, a variant of traditional CCD technology that is well suited for operation in light starved conditions. Despite successful implementation on many ground-based instruments, the technology has yet to be used within a space environment and therefore has low technological maturity compared to the standard CCD counterpart. Improvement of the technological matur
APA, Harvard, Vancouver, ISO, and other styles
15

Otten, Gilles P. P. L., Frans Snik, Matthew A. Kenworthy, et al. "ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624015.

Full text
Abstract:
We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of 2-5 mu m. and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The coronagraph manipulates the phase in the pupil to produce three beams yielding two coronagraphic point-spread functions (PSFs) and one faint leakage PSF. The phase pattern is imposed through the inherently achromatic geometric phase, enabled by liquid crystal technology and polarization techniques. The coronagraphic optic is manufactured using a direct-write tech
APA, Harvard, Vancouver, ISO, and other styles
16

Forsberg, Pontus. "Diamond Microfabrication for Applications in Optics and Chemical Sensing." Doctoral thesis, Uppsala universitet, Mikrosystemteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-192567.

Full text
Abstract:
Diamond is a material with many exceptional properties. In this thesis methods for fabrication of microstructures as well as several applications of such structures in optics, microfluidics and electrochemistry are presented. A method for etching deep and highly precise gratings is described. This method was used to fabricate circularly symmetric half wave plates for use in vector vortex coronagraphs. Such coronagraphs are a very promising approach to the direct imaging of extrasolar planets. By varying the lateral etch rate of the aluminum mask during diamond etching in an inductively coupled
APA, Harvard, Vancouver, ISO, and other styles
17

Vassallo, Daniele. "A virtual coronagraphic test bench for SHARK-NIR, the second-generation high-contrast imager for the Large Binocular Telescope." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3422319.

Full text
Abstract:
SHARK-NIR is the second-generation high-contrast coronagraphic imager for the Large Binocular Telescope (LBT). In my Ph.D. project I have been involved in the conceptual and final design phase of the instrument. In specific, I developed a simulator in IDL language that operated as a virtual test bench to make a comparative study of several coronagraphic techniques identified as suitable candidates for implementation in the instrument. The simulator is based on physical optics propagation and adopts an end-to-end approach to generate images in presence of several sources of optical aberrations
APA, Harvard, Vancouver, ISO, and other styles
18

Mawet, Dimitri, Élodie Choquet, Olivier Absil, et al. "CHARACTERIZATION OF THE INNER DISK AROUND HD 141569 A FROM KECK/NIRC2 L-BAND VORTEX CORONAGRAPHY." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625206.

Full text
Abstract:
HD 141569 A is a pre-main sequence B9.5 Ve star surrounded by a prominent and complex circumstellar disk, likely still in a transition stage from protoplanetary to debris disk phase. Here, we present a new image of the third inner disk component of HD 141569 A made in the L' band (3.8 mu m) during the commissioning of the vector vortex coronagraph that has recently been installed in the near-infrared imager and spectrograph NIRC2 behind the W.M. Keck Observatory Keck II adaptive optics system. We used reference point-spread function subtraction, which reveals the innermost disk component from
APA, Harvard, Vancouver, ISO, and other styles
19

Chipman, Russell A. "Advances in modeling polarimeter performance." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/626492.

Full text
Abstract:
Artifacts in polarimeters are apparent polarization features which are not real but result from the systematic errors in the polarimeter. The polarization artifacts are different between division of focal plane, spectral, and time modulation polarimeters. Artifacts result from many sources such as source properties, micropolarizer arrays, coatings issues, vibrations, and stress birefringence. A modeling examples of polarization artifacts due to a micro-polarizer array polarimeter is presented.
APA, Harvard, Vancouver, ISO, and other styles
20

Newman, Kevin, and Kevin Newman. "Achromatic Phase Shifting Focal Plane Masks." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621110.

Full text
Abstract:
The search for life on other worlds is an exciting scientific endeavor that could change the way we perceive our place in the universe. Thousands of extrasolar planets have been discovered using indirect detection techniques. One of the most promising methods for discovering new exoplanets and searching for life is direct imaging with a coronagraph. Exoplanet coronagraphy of Earth-like planets is a challenging task, but we have developed many of the tools necessary to make it feasible. The Phase-Induced Amplitude Apodization (PIAA) Coronagraph is one of the highest-performing architectures for
APA, Harvard, Vancouver, ISO, and other styles
21

Estevez, Dimitri. "Keplerian-Stacker: A new technique for coronagraphic images to increase the signal to noise ratio and detect exoplanets with direct imagning instruments." Thesis, KTH, Fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210306.

Full text
APA, Harvard, Vancouver, ISO, and other styles
22

Stenborg, Guillermo Adrián. "Interpretation and analysis on various time scales of narrow band coronal oberservations obtained with a new coronagraph system." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=963589644.

Full text
APA, Harvard, Vancouver, ISO, and other styles
23

Braga, Carlos Roberto. "Study of solar-interplanetary-geomagnetic disturbances using data from the Global Muon Detector Network and the LASCO coronagraph." Instituto Nacional de Pesquisas Espaciais, 2011. http://urlib.net/sid.inpe.br/mtc-m19/2011/02.07.20.31.

Full text
Abstract:
O objetivo do trabalho da Dissertação é estudar distúrbios solar-interplanetário-geomagnéticos, como ejeções de massa coronais solares (Coronal Mass Ejections - CMEs) usando observações de coronógrafos de luz branca e de raios cósmicos de alta energia (muons). A partir de imagens do coronógrafo LASCO-C3 (Large Angle and Spectroscopic Coronagraph), ejeções coronais de massa (CMEs) foram segmentadas de forma supervisionada por textura. O contorno identificado foi utilizado para estimar velocidades radiais e de expansão de um conjunto de 57 CMEs associadas a eventos solares próximos ao limbo. Opt
APA, Harvard, Vancouver, ISO, and other styles
24

Braga, Carlos Roberto. "Study of coronal mass ejections and their corresponding interplanetary structures using combined observations of cosmic ray detectors and coronagraphs." Instituto Nacional de Pesquisas Espaciais (INPE), 2015. http://urlib.net/sid.inpe.br/mtc-m21b/2015/01.30.19.09.

Full text
Abstract:
This Thesis aims to study coronal mass ejections (CMEs) and their interplanetary counterparts (ICMEs) using remove sensing observations from the solar corona, interplanetary in situ data and observations from ground-based cosmic ray detectors. CMEs have a central role on the Sun-Earth relationships because they are one of the main sources of geomagnetic disturbances. We have started the analysis by using a list of magnetic clouds (MCs) observed in the Earth-vicinity from 2008 to 2011. After probing the interplanetary structure, we identified the CMEs ejected in appropriate time and direction t
APA, Harvard, Vancouver, ISO, and other styles
25

Femenía, Castellá Bruno, Eugene Serabyn, Dimitri Mawet, et al. "Commissioning and first light results of an L'-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622007.

Full text
Abstract:
On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph operates in the L' band not only in order to take advantage from the favorable star/planet contrast ratio when observing beyond the K band, but also to exploit the fact that the Keck II Adaptive Optics (AO) system delivers nearly extreme adaptive optics image quality (Strehl ratios values near 90%) at 3.7 mu m. We describe the hardware installation of the vortex phase mask during a routine NIRC2
APA, Harvard, Vancouver, ISO, and other styles
26

Kosová, Petra. "Numerické metody zpracování obrazů z kosmického koronografu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400457.

Full text
Abstract:
Úkolem této práce je vytvoření adaptivního filtru pro vizualizaci CME v obrazech z kosmického koronografu, jejich implementování a výsledné testování na datech z kosmické sondy SOHO. V práci je zahrnuta potřebná teorie z oblasti astronomie a matematiky, popis NRGF, navrhnuté úpravy tohoto filtru a je přiložen program, který sloužil k jejich otestování.
APA, Harvard, Vancouver, ISO, and other styles
27

Hinrichs, Johannes [Verfasser]. "Analysis of Space Weather Impacts on the Terrestrial Ionosphere and Development and Testing of a Coronagraph for Space Weather Forecasts / Johannes Hinrichs." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1214440207/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
28

Jovanovic, N., O. Guyon, J. Lozi, et al. "The SCExAO high contrast imager: transitioning from commissioning to science." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622018.

Full text
Abstract:
SCExAO is the premier high-contrast imaging platform for the Subaru Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K band) with stable pointing and coronagraphs with extremely small inner working angles, optimized for imaging faint companions very close to the host. In the visible, it has several interferometric imagers which offer polarimetric and spectroscopic capabilities. A recent addition is the RHEA spectrograph enabling spatially resolved high resolution spectroscopy of the surfaces of giant stars, for example. New capabilities on the horizon include post-coronagraphi
APA, Harvard, Vancouver, ISO, and other styles
29

Rougeot, Raphaël. "Calculs de diffraction pour les coronographes solaires en vol en formation : Application pour ASPIICS." Thesis, Université Côte d'Azur, 2020. https://tel.archives-ouvertes.fr/tel-03177643.

Full text
Abstract:
La future mission PROBA-3 de l'ESA démontrera le vol en formation de satellites. Elle emportera à son bord le coronographe solaire géant ASPIICS. Un satellite portera un disque de 1,42m de diamètre afin d'occulter le Soleil. Un second satellite embarquera un coronographe de Lyot et se positionnera dans l'ombre du premier à 150m, avec une précision millimétrique. ASPIICS observera la région interne de la couronne du Soleil entre 1,1 et 3,0 rayons solaires, qui reste relativement inexplorée. La brillance de la couronne y est très peu intense, de six à dix ordres de grandeur plus faible que celle
APA, Harvard, Vancouver, ISO, and other styles
30

Venet, Melanie. "Coronographes spatiaux : Solar Orbiter / Metis, Smese / Lyot, Proba-3 / Aspiics." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10011.

Full text
Abstract:
La couronne solaire est la partie de l'atmosphère du Soleil qui s'étend de la photosphère (surface solaire d'où sont émis les photons) jusque dans le milieu interplanétaire. Sa compréhension relève d'un enjeu majeur car elle est à l'origine de phénomènes qui peuvent perturber les télécommunications, les êtres vivants et même le climat. L'instrument privilégié pour l'observer est le coronographe, système optique occultant le disque solaire au profit de la couronne, un million de fois moins intense. Ma thèse porte sur son étude, en particulier à travers les projets spatiaux :- SOLAR ORBITER, qui
APA, Harvard, Vancouver, ISO, and other styles
31

Herscovici-Schiller, Olivier. "Analyse et correction de surface d’onde post-coronographique pour l’imagerie d’exoplanètes." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEO022/document.

Full text
Abstract:
L’imagerie d’exoplanètes est limitée par deux obstacles intrinsèques : le faible écart angulaire entre planète et étoile, et le très faible flux lumineux en provenance de la planète par rapport à la lumière de l’étoile. Le premier obstacle est surmonté par l’utilisation de très grands télescopes, de la classe des dix mètres de diamètre, et éventuellement depuis le sol de systèmes d’optique adaptative, qui permettent d’atteindre de hautes résolutions angulaires. Le deuxième obstacle est surmonté par l’utilisation de coronographes. Les coronographes sont des instruments conçus pour filtrer la lu
APA, Harvard, Vancouver, ISO, and other styles
32

Anzolin, Gabriele. "Astronomical applications of optical vortices." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426036.

Full text
Abstract:
Optical vortices represent a particular class of wavefront dislocations characterized by a topological charge l. The surface of constant phase of an electromagnetic wave carrying an optical vortex has a helical structure and presents a singularity along the axis of the helicoid, where the phase is undefined. As a consequence, the intensity distribution of a vortex light beam contains a central dark region, where the intensity is zero due to destructive interference. Optical vortices can be produced by using phase modifying devices, i.e. particular optical elements possessing an optical singula
APA, Harvard, Vancouver, ISO, and other styles
33

Paul, Baptiste. "Mesure de front d'onde post-coronographique à haute précision pour l'imagerie à haut contraste : appplication sol et espace." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4731/document.

Full text
Abstract:
L'observation directe des exoplanètes est rendue difficile par l'énorme contraste entre la planète et l'étoile autour de laquelle elle gravite, ainsi que la faible séparation angulaire entre ces deux corps. Un tel niveau de contraste aussi proche de l'étoile être atteint en couplant l'imagerie à haute résolution angulaire et la coronographie, qui atténue le flux en provenance de l'étoile ; les performances ultimes d'un instrument d'imagerie à haut contraste sont alors limitées par ses aberrations quasi-statique. Au cours de cette thèse a été conçu un ASO plan focal dédié à la calibration des a
APA, Harvard, Vancouver, ISO, and other styles
34

Bourget, Pierre. "Coronographie à masque adaptatif pour imagerie et détection à haute dynamique." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4375.

Full text
Abstract:
L’imagerie à très haute dynamique s’applique à de nombreux domaines de recherche en astronomie et astrophysique. Cette problématique observationnelle est abordée sur plusieurs fronts par de nombreuses techniques complémentaires : coronographie, interferométrie, optique adaptative, controle de front d’onde et discrimination des speckles. La combinaison de celles ci permet d’atteindre un haut contraste avec pour ultime objectif l’imagerie d’exoplanètes et l’étude de l’environnement stellaire. Le travail présenté dans ce manuscrit se focalise sur la coronographie et plus particulièrement sur l’op
APA, Harvard, Vancouver, ISO, and other styles
35

Laugier, Romain. "Observables robustes pour la détection haut-contraste à faible séparation angulaire." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4046.

Full text
Abstract:
L'étude des exoplanètes est un domaine très actif. Malgré la nature indirecte de la plupart des détections, celles-ci nous fournissent déjà une quantité importante d'informations sur les propriétés de ces systèmes exoplanétaires: leur masse, taille et paramètres orbitaux. Pourtant, la détection directe de la lumière qu'elles émettent ou réfléchissent fournit des informations encore plus précieuses. Les instruments coronographiques conçus dans ce but sont généralement limités par la qualité de front d'onde, qui les empêchent notamment d'atteindre leurs performances théoriques. A l'inverse les t
APA, Harvard, Vancouver, ISO, and other styles
36

Mari, Elettra. "Optical vortex diffractive optics for terrestrial and space applications." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422490.

Full text
Abstract:
Optical vortices are topological dislocations due to phase singularities in light beams carrying orbital angular momentum (OAM). The wavefront of the electromagnetic wave that carries OAM is twisted around its axis of propagation, with a helicoidal shape. Along the axis of the helicoid the phase is undefined, so the waves cancel each other out. Hence, the intensity distribution of a vortex presents a dark core due to the destructive interference, that is surrounded by a ’ring of light’. The vortex is characterized by a number, called the topological charge that indicates how many 2π-twists the
APA, Harvard, Vancouver, ISO, and other styles
37

Hinrichs, Johannes. "Analysis of Space Weather Impacts on the Terrestrial Ionosphere and Development and Testing of a Coronagraph for Space Weather Forecasts." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1429-7.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Stenborg, Guillermo Adrian. "Interpretation and Analysis on Various Time Scales of Narrow-Band Coronal Oberservations Obtained with a New Coronagraph System." Doctoral thesis, 2000. http://hdl.handle.net/11858/00-1735-0000-0022-5D6F-1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
39

Douglas, Ewan S. "Advancing spaceborne tools for the characterization of planetary ionospheres and circumstellar environments." Thesis, 2016. https://hdl.handle.net/2144/19717.

Full text
Abstract:
This work explores remote sensing of planetary atmospheres and their circumstellar surroundings. The terrestrial ionosphere is a highly variable space plasma embedded in the thermosphere. Generated by solar radiation and predominantly composed of oxygen ions at high altitudes, the ionosphere is dynamically and chemically coupled to the neutral atmosphere. Variations in ionospheric plasma density impact radio astronomy and communications. Inverting observations of 83.4 nm photons resonantly scattered by singly ionized oxygen holds promise for remotely sensing the ionospheric plasma density.
APA, Harvard, Vancouver, ISO, and other styles
40

Stenborg, Guillermo Adrián [Verfasser]. "Interpretation and analysis on various time scales of narrow band coronal oberservations obtained with a new coronagraph system / vorgelegt von Guillermo Adrián Stenborg." 2000. http://d-nb.info/963589644/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the bibliographies on the topic 'Coronagraphie' for other source types:
Journal articles Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography