THE STATUS AND FUTURE OF THE ICRF

ABSTRACT. The International Celestial Reference Frame is currently defined by the radio positions of 212 extragalactic objects. Since its inception there have been two extensions to the ICRF. These extensions included revised positions of ICRF candidate and “other ” sources, based on inclusion of additional observations, as well as positions of an additional 109 “new ” sources. With continued applicable VLBI observations and improvements in analysis a better realization of the ICRF is now possible and an even better realization is feasible in the foreseeable future. Planning for a second realization of the ICRF is currently underway with a projected completion date concurrent with the 2009 IAU General Assembly. Within the next decade, optical astro-metric satellites will present serious competition to the radio based ICRF. Reevaluation of the spectral regime at which the ICRF is defined will then be necessary