The astrometric instrument of Gaia: Principles

    Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review

    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.
    Original languageEnglish
    Title of host publicationEuropean Space Agency, (Special Publication) ESA SP
    PublisherEuropean Space Agency
    Pages29-34
    Volume576
    Publication statusPublished - 2005
    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
    Country/TerritoryFrance
    CityParis
    Period2004/10/042004/10/07

    Subject classification (UKÄ)

    • Astronomy, Astrophysics and Cosmology

    Free keywords

    • Accuracy
    • Parallax
    • Gaia
    • ESA

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