POINTS: A Global Reference Frame Opportunity

  • J. F. Chandler
  • R. D. Reasenberg
Part of the International Astronomical Union / Union Astronomique Internationale book series (IAUS, volume 141)


POINTS is a space-based optical astrometric interferometer, capable of measuring the angular separation of two stars about 90° apart with 5-microarcsec (μas) 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, will establish a “rigid” reference grid with 0.5 μas position uncertainties. At that level, the grid will be free of regional biases and tied to the extra-Galactic frame that is our 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 will be tied through stellar aberration to the grid at about 300 μas. Additional targets of interest, to a limiting magnitude of greater than 20, will be 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 will severely test the assumption of cosmological quasar distances and may also constrain models of the early Universe.


Proper Motion Hubble Space Telescope Reference Star Extragalactic Radio Source Very Large Array 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bartel, N., Herring, T.A., Ratner, M.I., Shapiro, I.I., and Corey, B.E. (1986). VLBI limits on the proper motion of the ‘core’ of the superluminal quasar 3C345, Nature 319, 733–738.ADSCrossRefGoogle Scholar
  2. Eichhorn, H. (1974). Astronomy of Star Positions (Frederick Ungar Publishing, NY).Google Scholar
  3. Field, G. (1990). Private communication.Google Scholar
  4. Fricke, W. et al., (1988). Veröffentl. Astron. Rechen-Institut, Heidelberg, N. 32.Google Scholar
  5. Johnston, K.J., de Vegt, C., Florkowski, D.R., and Wade, C.M. (1985). Astron. J. 90, 2390.ADSCrossRefGoogle Scholar
  6. Kovalevsky, J. (1984). Sp. Sci. Rev. 39, 1–63.ADSCrossRefGoogle Scholar
  7. Podobed, V.V. (1965). Fundamental Astrometry, Translated from the Russian by A.N. Vyssotsky, The University of Chicago Press.Google Scholar
  8. Reasenberg, R.D. et al. (1988a). Astron. J. 96, 1731.ADSCrossRefGoogle Scholar
  9. Reasenberg, R.D., Babcock, R.W., Chandler, J.F., and Shapiro, I.I. (1988b). In Proceedings of the International Symposium on Experimental Gravitational Physics, edited by Hu Enke and P. Michelson.Google Scholar
  10. Veron-Cetty, M.-R, and Veron, P. (1987). “A Catalog of Quasars and Active Nuclei”, ESO Scientific Report No. 5 (Garching: ESO).Google Scholar

Copyright information

© IAU 1990

Authors and Affiliations

  • J. F. Chandler
    • 1
  • R. D. Reasenberg
    • 1
  1. 1.Smithsonian Astrophysical ObservatoryCambridgeUSA

Personalised recommendations