U.S. Naval Observatory Astrometry Department

The Radio Optical Reference Frame
Optical Image Database (OID)

[CCD Image of 0003+380]

Presented here are preliminary results of an ongoing program to obtain precise optical positions of the RORF sources. The radio frame, defined by the positions of selected extragalactic radio sources, can now be established to an accuracy of better than one milliarcsecond. This defines a frame that is more accurate than the projected internal accuracy of the HIPPARCOS catalog and far exceeds that of the Fifth Fundamental Catalog (FK5). Because of the need to link these optical reference frames to the radio, it is important to include in the radio catalog objects that are detectable at both radio and optical wavelengths. In this way, the accuracy of the optical catalogs can be improved, including the proper motions.

Last modified: Wed Jun 13 09:43:40 EDT 2001
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