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POINTS - A global reference frame opportunityPOINTS is a space-based optical astrometric interferometer capable of measuring the angular separation of two stars about 90 degrees apart with 5-microarcsec nominal accuracy . During the intended ten-year mission, a repeated survey of a few hundred targets over the whole sky, including a few bright quasars, establish a 'rigid' reference grid with 0.5 microarcsec position uncertainties. At that level, the grid is free of regional biases and tied to the extra-Galactic frame that is the present best candidate for an inertial frame. POINTS will also determine parallaxes and annual proper motions at about the same level. Further, the planetary ephemeris frame is tied through stellar aberration to the grid at about 300 microarcsec. Additional targets of interest, to a limiting magnitude of greater than 20, are observed relative to the grid, yielding determinations with uncertainties depending on the observing schedule. Measurement at the microarcsec/year level of the apparent relative velocities of quasars that are widely separated on the sky severely test the assumption of cosmological quasar distances and may also constrain models of the early universe.
Document ID
19910070141
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Chandler, J. F.
(Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Reasenberg, R. D.
(Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Astronomy
Meeting Information
Meeting: Symposium of the IAU
Location: Leningrad
Country: USSR
Start Date: October 17, 1989
End Date: October 21, 1989
Accession Number
91A54764
Funding Number(s)
CONTRACT_GRANT: NAGW-1647
CONTRACT_GRANT: NAGW-1355
Distribution Limits
Public
Copyright
Other

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