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Paper: Radio Astrometry: Present Status and Future
Volume: 338, Astrometry in the Age of the Next Generation of Large Telescopes
Page: 335
Authors: Fomalont, E.B.
Abstract: The highest astrometric precision presently comes from very long baseline interferometric observations at radio frequencies. The fundamental reference frame is defined by a set of quasar positions, and has an orientation accuracy of 0.02 mas. This will be the standard until optical-observing satellites obtain an increased precision by about a factor of ten. Parallaxes, proper motions and orbit elements of stellar systems are now being obtained with 0.04 mas accuracy. Increased astrometric accuracy of a factor of three is anticipated within seven years with ALMA at high frequencies where hundreds of nearby stars will be detected. The SKA with its enormous sensitivity for stellar observations may be available by 2017.
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