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Reference Frames

SIM will yield 4 microarcsecond (mas) absolute position and parallax measurements. In order to accomplish this, SIM will define a new astrometric reference frame, using a grid of approximately 1300 stars with positions accurate to 4 mas. Unlike most survey instruments, SIM will maintain its astrometric accuracy down to the faintest magnitudes. This ability opens up the opportunity for astrometry of active galactic nuclei to better than 10 mas at magnitudes fainter than about 16.

A precision frame tie between optical and radio frames provided through astrometry of optical (radio-loud) quasars by SIM. The current radio-based (quasar) reference frame is the International Celestial Reference Frame, which is tied to optical observations through observations of radio-bright stars with Hipparcos. Chromospherically active stars are very interesting scientifically, but they make poor reference objects because of their extended sub-structure (see Stellar Astrophysics). By using quasars, the SIM frame tie will eliminate the need to rely on stars.

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Extrasolar planets, NASA exterrestrial extrasolar planets around nearby stars. SIM Space Interferometory Mission. Keck Interferometer. Terrestrial Planet Finder. Extrasolar planets, or exoplanets. Extraterrestrial. Exo-planets life space, outer space.

Extrasolar planets. Exo-planets. Searching for extrasolar planets. Searching for exo-planets. Earth-like planets in the Milky Way. Exoplanets and extra-solar planets, or exoplanets and extra-solar planets. Planets around others stars are called extrasolar planets. What is an extrasolar planet? Astronomy, or astronomy and finding planets. National Aeronautics and Space AdministrationJet Propulsion Laboratory WebsiteCalifornia Institute of Technology Website JPL Website Home PageJPL Website - EarthJPL Website - Solar SystemJPL Website - Stars and GalaxiesJPL Website - Technology Planet Quest Home PageSpace Interferometry Mission Home Page