Related papers: Interviews about modern astrometry
Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging…
The great development of astrometric accuracy since the observations by the Greek astronomer Hipparchus about 150 BC has often been displayed in diagrams showing the accuracy versus time. Two new diagrams are provided here, one for…
We present the results of realistic end-to-end simulations of observations of nearby stars with the proposed global astrometry mission GAIA, recently recommended within the context of ESA's Horizon 2000 Plus long-term scientific program. We…
Over the last 20 years Hubble Space Telescope Fine Guidance Sensor interferometric astrometry has produced precise and accurate parallaxes of astrophysical interesting stars and mass estimates for stellar companions. We review parallax…
In this concluding article I recall the early history of the Gaia mission, showing that the original science case and expectations of wide community interest in Gaia data have been met. The quarter-century long partnership involving some…
Gaia Data Release 1 (Gaia DR1) contains astrometric results for more than 1 billion stars brighter than magnitude 20.7 based on observations collected by the Gaia satellite during the first 14 months of its operational phase. We give a…
A new mission about twenty years after Gaia with similar astrometric performance would be important for all branches of astronomy. The two missions together would, e.g., give much more accurate motions of the common objects due to the large…
The Gaia mission is expected to provide highly accurate astrometric, photometric, and spectroscopic measurements for about $10^9$ objects. Automated classification of detected sources is a key part of the data processing. Here a few aspects…
The first release of astrometric data from Gaia is expected in 2016. It will contain the mean stellar positions and magnitudes from the first year of observations. For more than 100 000 stars in common with the Hipparcos Catalogue it will…
This article is a sort of sequel of the earlier extensive review by Saha (1999a) where emphasis was laid down on the ground based single aperture, as well as on the working long baseline optical interferometers (LBI) situated at the various…
The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial velocities for over one hundred…
Gaia is the cornerstone mission of the European Space Agency. From late 2013 it will start collecting superb astrometric, photometric and spectroscopic data for around a billion of stars of our Galaxy. While surveying the whole sky down to…
Astrometry is a powerful technique in astrophysics to measure three-dimensional positions of stars and other astrophysical objects, including exoplanets and the gravitational influence they have on each other. Interferometric astrometry is…
Gaia's astrometric solution aims to determine at least five parameters for each star, together with appropriate estimates of their uncertainties and correlations. This requires at least five distinct observations per star. In the early data…
ESA's Gaia space astrometry mission is performing an all-sky survey of stellar objects. At the beginning of the nominal mission in July 2014, an operation scheme was adopted that enabled Gaia to routinely acquire observations of all stars…
In real telescopes, the optical parameters evolve with time, and the degradation is often not uniform. This introduces variations in the image profile and therefore photo-centre displacements which, unless corrected, may result in…
GAIA will provide a multi-colour photometric and astrometric census of some one billion compact sources, complete to 20th magnitude. In addition, spectra for radial velocities will be obtained for about 30 million stars brighter than V=17.…
General relativistic effects in astrophyiscal systems have been detected thanks to accurate astrometric measurements. We outline some keystones of astrometry such as stellar aberration (argument development during the years 1727-1872);…
In this article, I will present some figures and milestones of the written production of the Instituto Argentino de Radioastronomia (IAR), as well as a personal review of the scientific achievements carried out in recent years by the…
The era of high-precision astrometry has dawned upon us. The potential of Gaia $\mu$as-level precision in positional measurements is about to be unleashed in the field of extrasolar planetary systems. The Gaia data hold the promise for much…