POINTS is by design a global astrometry instrument, capable of constructing a bias-free
GRF
accurate to a few microarcseconds over the entire celestial sphere. Such a reference frame will
be about three orders of magnitude more accurate than the likely best available optical reference
frame. From observations of bright quasars and
AGN, as well as radio stars,
[73]
the POINTS GRF
will be tied directly to the radio frame. Hence, systematic errors in the radio frame may be found
and characterized, and determination of the coincidence between radio and optical emissions will
be greatly improved. Further, we can place significant bounds on the proper motions of bright,
well-separated quasars, with subsequent cosmological implications.
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POINTS Science
16:29 Wednesday, January 03, 1996
page 20 of 20
[73]
Walter, H.G., Hering, R., and De Vegt, Ch., 1990, Astron & Astrophys Supp 86, 357, "An Astrometric Catalogue
of Radio Stars";
White, G.L., Jauncey, D.L., Harvey, B.R., Savage, A., Gulkis, S., and Preston, R.A., 1991, Astrophys. Space Sci.
177, 79, "Astrometry of Southern Radio Sources";
Xu, T.-Q., Lu, P.-Z., Wang, S.-H., and Chu, Z.-Y., 1991, Chinese Astr. Astrophys. 15, 19, "Optical Positions of
Radio Stars and Radio Sources";
Requieme, Y., and Mazurier, J.M., 1991,
Astron
& Astrophys Supp 89, 311, "Optical Positions of 221 Radio Stars
Obtained with the Bordeaux Automatic Meridian Circle";
Lestrade, J.-F., Phillips, R.B., Preston, R.A., and Gabuzda, D.C., 1992, Astron & Astrophys 258, 112, "High-
Precision VLBI Astrometry of the Radio-Emitting Star Sigma CrB - A Step in Linking the Hipparcos and Extraga-
lactic Reference Frames"
