WorldCat Identities

Teixeira, Ramachrisna

Overview
Works: 11 works in 14 publications in 3 languages and 48 library holdings
Genres: Conference papers and proceedings 
Roles: Author, Thesis advisor, Editor, Other, 958, Opponent
Classifications: QB349, 521.1
Publication Timeline
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Most widely held works by Ramachrisna Teixeira
IV Reunión sobre Astronomía Dinámica en Latinoamerica (ADeLA 2008) : México, D.F., México, febero 12-16, 2008 by Reunión sobre Astronomía Dinámica en Latino-América( Book )

2 editions published in 2008 in English and held by 34 WorldCat member libraries worldwide

Astrometry in Latin-America : Proceendings of the Latin-American Meeting on Astrometry ADeLA, 2, Araraquara, São Paulo-Br, 2-5 September, 2002 by Ramachrisna Teixeira( Book )

1 edition published in 2004 in English and held by 3 WorldCat member libraries worldwide

Traitement global des observations méridiennes de l'Observatoire de Bordeaux by Ramachrisna Teixeira( )

2 editions published in 1990 in French and held by 3 WorldCat member libraries worldwide

USUELLEMENT LES OBSERVATIONS MERIDIENNES SONT GROUPEES EN SERIES QUI SONT REDUITES SEPAREMENT, ET LE SYSTEME INSTRUMENTAL EST FIXE PAR LES OBSERVATIONS D'ETOILES DE REPERE. DANS CE TRAVAIL, NOUS TRAITONS LES DONNEES ACQUISES PENDANT DEUX ANS AVEC LA LUNETTE MERIDIENNE DE BORDEAUX, EN CONSIDERANT SIMULTANEMENT TOUTES LES OBSERVATIONS. AINSI, NOUS SOMMES AMENES A RESOUDRE UN SEUL PROBLEME DE MOINDRES CARRES DONT LES INCONNUES NE SONT PLUS UNIQUEMENT LES PARAMETRES INSTRUMENTAUX MAIS AUSSI LES POSITIONS DE TOUTES LES ETOILES. DANS CE CAS, TOUTES LES ETOILES CONTRIBUENT A LA DEFINITION DU SYSTEME INSTRUMENTAL ET, PAR CONSEQUENT, NOUS SOMMES MOINS TRIBUTAIRES DES CATALOGUES DE REPERE. LES SOLUTIONS DU SYSTEME D'EQUATIONS RESULTANT, QUI CONTIENT QUELQUES DIZAINES DE MILLIERS D'EQUATIONS ET DES MILLIERS D'INCONNUES ET EST SINGULIER, SONT OBTENUES PAR UNE ADAPTATION DE LA METHODE ITERATIVE DE GAUSS-SEIDEL. LA CONVERGENCE DES ITERATIONS EST DEMONTREE ET LES RESULTATS AINSI OBTENUS SONT PRESENTES ET ANALYSES
4. reunion sobre astronomia dinamica en latinoamerica (ADeLA 2008), Mexico, D.F., febrero 12-16, 2008( Book )

1 edition published in 2008 in English and held by 2 WorldCat member libraries worldwide

Plus loin avec la mission spatiale Gaia grâce à l'analyse des objets étendus by Alberto Krone-Martins( )

1 edition published in 2011 in French and held by 1 WorldCat member library worldwide

The main objective of this work is to determine whether it is possible to do science from the observations of extended objects that will be performed by the Gaia space mission. One of the most ambitious projects of modern Astronomy, this mission will observe more than one billion objects through out the sky, thus providing astrometric, photometric and spectroscopic data with unprecedented precision. Naturally, Gaia has been optimized for the study of point-like sources due to its astrometrical priority. Nevertheless, many sources associated with extended emission will be observed. The origins of these extended sources can be either intrinsic, such as galaxies, or extrinsic, such as projections of objects in the same line of sight. In both cases, these sources will have less than optimal astrometric solutions.In order to study those emissions, their two-dimensional images will be analyzed. Nonetheless, since Gaia will not acquire such images, we begin this work by checking whether it will be possible to reconstruct images anywhere in the sky from the satellite's one-dimensional observations.Consequently, we, on the one hand, estimate the number of cases which will be subjected to the extrinsic extended emissions, present a method which we developed to analyze the reconstructed images by segregating the different sources and show that the adoption of this method will allow extending the catalogue reliably by millions of point sources, many of which are beyond the limiting magnitude of the instrument. On the other hand, regarding intrinsic extended emissions, we first obtain an upper limit estimate for the number of cases which Gaia will be able to observe ; then,we verify that the combination of image reconstructions and the use of the codes introduced here in will allow performing the morphological classification of millions of galaxies in early/late types and elliptical/spiral/irregular classes. Afterward,we present a method which we developed to decompose those galaxies into their bulge/disk components directly from the one-dimensional Gaia data in a completely automatic way. Finally, we conclude that it is possible to harness the data of many of the observations that might other wise be ignored to do science. Saving these data will allow the detection of millions of objects beyond Gaia's limiting magnitude and the study of the morphology of millions of galaxies whose structures can only be probed from space or through the adoption of adaptive optics, thus somewhat expanding the horizons of this already comprehensive mission
Division I : Working Group Astrometry by Small Ground-Based Telescopes by William Thuillot( Book )

1 edition published in 2009 in English and held by 1 WorldCat member library worldwide

"At the IAU XXVI General Assembly in 2006, the Division I decided to create the Working Group on Astrometry by Small Ground-Based Telescopes (WG-ASGBT). Its scientic goals are to foster the follow-up of small bodies detected by the large surveys including the NEOs; to set-up a dedicated observation network for the follow-up of objects which will be detected by Gaia; to contribute to the observation campaigns of the mutual events of natural satellites, stellar occultations, and binary asteroids; and to encourage teaching astrometry for the next generation. The present report gives the main activities carried out in these areas with small telescopes (diameter less than 2m)."
Extensão do ICRF em zonas selecionadas do céu até V=15,0 by Júlio Ignácio Bueno de Camargo( Book )

1 edition published in 2001 in Portuguese and held by 1 WorldCat member library worldwide

Neste trabalho, são apresentados resultados em direção à extensão do ICRF ao domínio óptico até V=15,0, em regiões de grande interesse para a Astronomia. Esta extensão é dada através de posições e movimentos próprios precisos referidos ao ICRS como materializado pelo catálogo Tycho-2. Posições de época atual foram obtidas com o círculo meridiano CCD do Observatório Abrahão de Moraes, situado na cidade de Valinhos, São Paulo. A derivação dos movimentos próprios é alcançada combinando-se posições obtidas através do círculo meridiano CCD com posições oriundas de catálogos astrométricos disponíveis e de medidas de placas SERC-J, realizadas com a máquina MAMA (Paris). O produto final é apresentado no formato de catálogo contendo posições, movimentos próprios, magnitudes e identificações cruzadas com outras importantes fontes de dados astrométricos para aproximadamente 180.000 objetos. A discrição do material empregado é dada juntamente com uma análise das incertezas sobre as posições e movimentos próprios do catálogo final. Um estudo estatístico para suporte da qualidade geral dos resultados como materialização óptica do ICRS também é apresentado. Em média, estrelas com V'OU='14,0 possuem precisões (Continua)
Second latin-american meeting on astrometry ADeLA / 2002 : Astrometry in Latin-America : proceeding of a meeting held in Araraquara, São Paulo - Br, 02-05 September / 2002 by Proceedings of the Latin-American Meeting on Astrometry ADeLA( Book )

1 edition published in 2004 in English and held by 1 WorldCat member library worldwide

Análise das observações meridianas fotoelétricas do Observatório de Bordeaux by Júlio Ignácio Bueno de Camargo( Book )

1 edition published in 1997 in Portuguese and held by 1 WorldCat member library worldwide

Este trabalho consiste na redução e subsequente análise dos resultados de um conjunto de mais de 170.000 observações efetuadas com o círculo meridiano fotoelétrico automático do Observatório de Bordeaus, no período compreendido de 1993 a 1992. Atécnica de redução utilizada (redução global) tem como base o método de "overlap", introduzido por Eichhorn na redução de placas fotográficas (Eichhron 1960), e representa uma extensão do trabalho desenvolvido por Teixeira et al. 1992 sobre umsubconjunto dessas observações, mais precisamente aquelas realizadas de 1986 a 1987 (teixeira 1990, Teixeira et al. 1992). Esta extensão ocorre por conta da introdução dos movimentos prórpios como incógnitas, além das posições e parâmetrosinstrumentais. A consideração destas novas incögnitas devido ao tempo relativamente longo que está sendo considerado, e principalmente à má qualidade dos movimentos próprios da maioria dos objetos observados. A análise dos resultados oriundosdessa redução fez-se segundo as seguintes abordagens: - Parâmetros Instrumentais, - Posições, - Movimentos Próprios, - Resíduos. Um levantamento estatístico das observações realizadas ao longo dos mencionados quase 10 anos de funcionamento desseinstrumento complementa este trabalho
Revista mexicana de astronomia y astrofisica. Serie de conferencias( Book )

1 edition published in 2008 in English and held by 1 WorldCat member library worldwide

Photométrie et Astrométrie des Satellites de Jupiter : application à la campagne de phénomènes mutuels 2015 by Eléonore Saquet( Book )

2 editions published in 2017 in French and held by 0 WorldCat member libraries worldwide

The year 2015 was a favorable opportunity for the mutual event observations of the galilean satellites of Jupiter. Mutual events occur when the Earth and the Sun cross the common plane of their orbits. This configuration happens every six years when the apparent Jovian declinations of Earth and Sun become zero.During this campaign, we observed 236 events, and we received more than 600 light curves. We developed an astrometric reduction of these light curves based on an existing model. To reduce the light curves, we used Hapke's model of reflectance and emittance.To improve the reduction method, we led an observational campaign to record photometric data of the galilean moons. This work was fundamental to upgrade the last photometric data on the galilean satellites. Ground based photometry of these moons had never been done in the methane band or in RGB bands.The astrometric data extracted from the light curves were used by V. Lainey to fit his dynamical model of the galilean satellites and build new ephemerides. Comparisons between ephemerides were made in order to evaluate the impact of the mutual event observations on the determination of the dynamical parameters
 
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