The astrometric instrument of Gaia: Principles

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding

Abstract

Compared with Hipparcos, Gaia will give an enormous improvement in accuracy, completeness and number of stars: about two orders of magnitude in accuracy, four orders in number, and a completeness limit that is 12 magnitudes fainter. How is all this possible? The answer is: by a combination of many factors, the most important being bigger and more efficient detectors, and bigger optics. The method of astrometric measurements by Gaia is described from first principles, and the fundamental limitations explained in terms of physics (diffraction and photon noise), geometry, temporal sampling and reference frames. Although Gaia is basically a self-calibrating instrument, things have to be stable enough over time scales that are long enough for the calibrations to be carried out, and the corresponding requirements are outlined. To achieve microarcsecond accuracy is technically extremely demanding, but feasible with a clever and careful design of the instrument.

Details

Authors
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology

Keywords

  • Accuracy, Parallax, Gaia, ESA
Original languageEnglish
Title of host publicationEuropean Space Agency, (Special Publication) ESA SP
PublisherEuropean Space Agency
Pages29-34
Volume576
Publication statusPublished - 2005
Publication categoryResearch
Peer-reviewedYes
EventSymposium - The Three-Dimensional Universe with Gaia - Paris, France
Duration: 2004 Oct 42004 Oct 7

Publication series

Name
Volume576
ISSN (Print)0379-6566
ISSN (Electronic)1609-042X

Conference

ConferenceSymposium - The Three-Dimensional Universe with Gaia
CountryFrance
CityParis
Period2004/10/042004/10/07