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In 1989, the European Space Agency's Hipparcos satellite took astrometry into orbit, where it could be less affected by mechanical forces of the Earth and optical distortions from its atmosphere.
Operated from 1989 to 1993, Hipparcos measured large and small angles on the sky with much greater precision than any previous optical telescopes.
During its 4-year run, the positions, parallaxes, and proper motions of 118, 218 stars were determined with an unprecedented degree of accuracy.
A new “ Tycho catalog ” drew together a database of 1, 058, 332 to within 20-30 mas ( milliarcseconds ).
Additional catalogues were compiled for the 23, 882 double / multiple stars and 11, 597 variable stars also analyzed during the Hipparcos mission.

1.835 seconds.