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Astrometry is the branch of astronomy concerned with the determination of positions, proper motions, and parallaxes of solar-system bodies, stars, and distant galaxies.  Astronomers at USNO use the latest instrumentation and methods to extend the accuracy and brightness limits of astrometric catalogs and reference frames.

  • Optical/IR Products

    Optical/infrared image and catalog products provided by the USNO.  Astrometric catalogs include NOMAD, UCAC, USNO-B1, Double Stars, etc.  Imaging products include digital scans of a number of the major Schmidt telescope surveys of the skies, along with the catalogs of astronomical objects created from those images.  Access to astrometric catalogs and imaging products is provided through the USNO Image and Catalog Archive Server.
  • VLBI-based Products

    Very Long Baseline Interferometry (VLBI) is a technique used by radio astronomers and geodesists to determine the celestial and terrestrial reference frames and to predict the variable orientation of the Earth in three-dimensional space.  Access to VLBI images is available through the Radio Reference Frame Image Database.
  • Astrometry Information Center

    Your one-stop-source for astrometry related information.