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Comparison of the Optical and Radio Reference Frames

Published online by Cambridge University Press:  30 March 2016

K. J. Johnston  and
Chr. de Vegt
K. J. Johnston
Affiliation:
E. O. Hulburt Center for Space Research, Naval Research, Laboratory, Washington, D. C.
Chr. de Vegt
Affiliation:
Hamburger Sternwarte, Hamburg, Germany

Extract

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The Very Large Array (VLA) has made possible the measurement of the precise positions of the radio emission associated with stars. This allows the direct comparison of the optical reference frame (FK4) with the radio reference frame which is defined by the quasi-absolute positions of extragalactic radio sources. This comparison is limited by the small number of bright stars that display detectable radio emission and the lack of knowledge of the precise coincidence of the radio emission with the optical photocenter of the star. Since the VLA is the most sensitive astrometrically capable radio telescope, positions of the largest number of stars north of declination -20 degrees can be measured. The accuracy of the positions on the extragalactic reference frame should approach a milliarcsecond.

Type
Joint Discussions
Information
Highlights of Astronomy , Volume 7: Highlights of Astronomy. As presented at the XIXth General Assembly of the IAU, 1985 , 1986 , pp. 103 - 108
Copyright
Copyright © Reidel 1986

References

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