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Optical SETI Advance

A huge cache of data has become available for the search for optical signals from extraterrestrial civilizations. The first catalog of more than a billion stars from the European Space Agency’s Gaia satellite was published in September. Because the catalogue contains the three-dimensional position of all optical sources that the spacecraft detects down to 20th magnitude, its repeated scans may capture persistent optical signals suggestive of intelligent communication.

Gaia’s mission is to perform spectral and photometric measurements of all objects that it detects, with a position accuracy of 24 microarc-seconds. The Gaia spacecraft carries a single integrated instrument that comprises three major functions: astrometry, photometry and spectrometry. The three functions use two common telescopes and a shared focal plane, with each function having a dedicated area on the large 0.5m × 1m CCD detector array. The instrument will provide accurate astrometry measurements, even in densely populated sky regions of up to 3 million stars/deg², continuous photometry spectra in the band 330-1050 nm, and high resolution- narrow band spectrometry between 845 and 872 nm.

All the data are available from the ESA Gaia Archive:


Eventually, the final catalogue will contain full astrometric (position, distance and motion) and photometric (brightness and colour) parameters for over one billion stars as well as extensive additional information including a classification of the sources and lists of variable stars, multiple stellar systems and exoplanet-hosting stars. It will also survey large numbers of solar asteroids and comets, nearby galaxies, and distant quasars.