Results 31 to 40 of about 7,595 (254)
Relativity in Astrometry [PDF]
The coordinate dependence of the definition of light deflexion is discussed and the concepts of “natural” and “proper” reference frame are introduced in order to derive astrometric observables from coordinate quantities. Confusion in published formulations of VLBI data analysis is discussed in the context of the IAU definition of the coordinate time ...
openaire +1 more source
Gaia: The Astrometry Revolution [PDF]
AbstractThe power of micro-arcsecond (μas) astrometry is about to be unleashed. ESA's Gaia mission, now headed towards the end of the first year of routine science operations, will soon fulfil its promise for revolutionary science in countless aspects of Galactic astronomy and astrophysics.
SOZZETTI, Alessandro+4 more
openaire +5 more sources
Halometry from astrometry [PDF]
Halometry---mapping out the spectrum, location, and kinematics of nonluminous structures inside the Galactic halo---can be realized via variable weak gravitational lensing of the apparent motions of stars and other luminous background sources. Modern astrometric surveys provide unprecedented positional precision along with a leap in the number of ...
Neal Weiner+2 more
openaire +3 more sources
Spectro-astrometry is applied to echelle spectra of the young intermediate-mass star T CrA. The aim is to better understand the origin of the [O i ] and [S ii ] emission from T CrA and further explore the usefulness of spectro-astrometry in the search ...
E. T. Whelan, A. Murphy, I. Pascucci
doaj +1 more source
Improved astrometry for the Bohannan & Epps catalogue [PDF]
Aims: Accurate astrometry is required to reliably cross-match 20th-century catalogues against 21st-century surveys. The present work aims to provide such astrometry for the 625 entries of the Bohannan & Epps (BE74) catalogue of H$\alpha$ emission-line stars.
arxiv +1 more source
RESULTS OF PROCESSING OF ASTRONEGATIVES WITH COMMERCIAL SCANNER
Astrometric errors depending on the method of scanning with different spatial resolutions were studied with commercial scanner such as Epson Perfection V750 Pro.
Yu. I. Protsyuk+3 more
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Companions embedded in the cavities of transitional circumstellar disks have been observed to exhibit excess luminosity at H α , an indication that they are actively accreting.
William O. Balmer+11 more
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The paper discusses and illustrates the steps of basic processing of digitized image of astro negatives. Software for obtaining of a rectangular coordinates and photometric values of objects on photographic plates was created in the environment ...
Yu. I. Protsyuk+2 more
doaj +1 more source
This catalogue contains the results of 1321 right ascensions observations of 2dj Radio References Stars obtained al Odessa with the Repsold transit circle in 1990-1993.
A. P. Chelombit'ko
doaj +1 more source
Determination of Orbital Elements and Ephemerides using the Geocentric Laplace’s Method
This paper presents a methodology for Initial Orbit Determination (IOD) based on a modification of the Laplace’s geocentric method. The orbital elements for Near-Earth asteroids (1864) Daedalus, 2003 GW, 2019 JA8, a Hungaria-type asteroid (4690 ...
Daniela Espitia+2 more
doaj +1 more source