Radio optical reference frame. 6: Additional source positions in the northern hemisphere

Fey, A. L.; Russell, J. L.; Vegt, C. de; Zacharias, N.; Johnston, K. J.; Ma, C.; Hall, David; Holdenried, E. R.

doi:10.1086/116862

Cited by 5 publications

(1 citation statement)

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“…These sources were all north of −30 degrees declination. This first program was followed by campaigns to increase the density of sources in the northern hemisphere and to add an equal grid of sources in the southern hemisphere (Russell et al , 1992Fey et al 1992Fey et al , 1994Reynolds et al 1994). These campaigns resulted in a catalog consisting of a total of 403 sources with 208 in the northern hemisphere and 195 in the southern hemisphere.…”

Section: The Radio Reference Framementioning

confidence: 99%

Reference Frames in Astronomy

Johnston¹,

Vegt²

1999

Annu. Rev. Astron. Astrophys.

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Key Words astrometry, reference frames, reference systems s Abstract Advances in wide-angle astrometric measurements of three to four orders of magnitude in the last thirty years have resulted in a redefinition of the fundamental astronomical reference frame. This new frame, the International Celestial Reference Frame (ICRF), is based on the radio positions of 212 compact extragalactic radio sources. The ICRF defines the direction of the axes of the International Celestial Reference System (ICRS) with a precision of approximately 20 µas. At optical wavelengths, the Hipparcos catalog is the realization of this frame. The precision with which the ICRF is now determined requires that the ICRS models for precession, nutation, and others, be revised. Increases in the precision of measurements from astrometric space missions will further improve the celestial reference frame and may require its redefinition within the next ten years. These improvements will again challenge the models for the celestial reference system.

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Section: The Radio Reference Framementioning

confidence: 99%