This 5-yr program which began in 1987 is to establish a link between the radio and optical reference frames, using about 400 extragalactic sources which are compact and flat spectrum in the radio and which are observable in the optical. An overview of the program is presented at this meeting by Johnston et al. Various specific aspects of it are also discussed in Ma et al., McCarthy et al. and Reynolds et al.
The observations have been continuing in both hemispheres and in both the radio and the optical. We have observed 348 sources with VLBI. There is at least one astrograph plate available for 369 sources and at least one prime focus plate available for 138 sources. Altogether there are 450 sources with some data.