Real-Time, Very-Long-Baseline Interferometry Based on the Use of a Communications Satellite

Science  21 Oct 1977:
Vol. 198, Issue 4314, pp. 289-291
DOI: 10.1126/science.198.4314.289


The Hermes satellite, a joint Canadian-American program, has been used to provide a communication channel between radio telescopes in West Virginia and Ontario, for very-long-baseline interferometry (VLBI). This system makes possible instantaneous correlation of the data as well as a sensitivity substantially better than that of earlier VLBI systems, by virtue of a broader observational bandwidth. With the use of a geostationary communications satellite it is possible to eliminate the tape recorders and the most troublesome part of the postobservational data processing. A further possibility is the development of a phase-coherent interferometer.