One good cosmic measure

  title={One good cosmic measure},
  author={L{\'e}o Girardi},
  pages={1001 - 1002}
Radio-wave interferometry provides an accurate measurement of cosmic distances [Also see Report by Melis et al.] As Earth orbits around the Sun, nearby stars are seen to move against the background of more distant stars and galaxies. The angular amplitude of this motion is called parallax and provides a direct, trigonometric measurement of the stellar distances as compared to the size of Earth's orbit. A great achievement of the European Space Agency's satellite Hipparcos (1) was the… 


Hipparcos, the New Reduction of the Raw Data
List of Figures. List of Tables. List of Acronyms. Preface. Introduction. Dedication. Part I The Hipparcos mission. 1. THE HIPPARCOS MISSION. 1.1 Overture. 1.2 The mission. 1.3 The published data.
A VLBI resolution of the Pleiades distance controversy
An absolute trigonometric parallax distance measurement to the Pleiades cluster that uses very long baseline radio interferometry (VLBI) is presented, which is the most accurate and precise yet presented for the cluster and is incompatible with the Hipparcos distance determination.
The Problem of Hipparcos Distances to Open Clusters. I. Constraints from Multicolor Main-Sequence Fitting*
Parallax data from the Hipparcos mission allow the direct distance to open clusters to be compared with the distance inferred from main-sequence (MS) fitting. There are surprising differences between
The problem of the Pleiades distance - Constraints from Strömgren photometry of nearby field stars
The discrepancy between the Pleiades cluster distance based on Hipparcos parallaxes and main sequence tting is investigated on the basis of Stromgren photometry of F-type stars. Field stars with the
Correlated Errors in Hipparcos Parallaxes toward the Pleiades and the Hyades
We show that the errors in the Hipparcos parallaxes toward the Pleiades and the Hyades open clusters are spatially correlated over angular scales of 2°-3°, with an amplitude of up to 2 mas. This
GAIA: Composition, formation and evolution of the Galaxy
The GAIA astrometric mission has recently been approved as one of thenext two ``cornerstones'' of ESA's science programme, with a launch datetarget of not later than mid-2012. GAIA will provide
Parallax beyond a Kiloparsec from Spatially Scanning the Wide Field Camera 3 on the Hubble Space Telescope
We use a newly developed observing mode on the Hubble Space Telescope (HST) and Wide Field Camera 3, spatial scanning, to increase source sampling a thousand-fold and measure changes in source
The astrometric core solution for the Gaia mission. Overview of models, algorithms, and software implementation
A comprehensive overview of the mathematical and physical models applicable to the astrometric core solution of the Gaia satellite, using a global solution approach, as well as its numerical and algorithmic framework is provided.
COM REFERENCES 1. The Hipparcos and Tycho Catalogues
  • ESA SP Series
  • 1997