John Bolton's Variable-baseline Interferometer and the Structure of Radio Galaxies

Abstract

John Bolton was a pioneer in the study of extragalactic radio sources, first at the CSIRO Radiophysics Laboratory and then at the California Institute of Technology's Owens Valley interferometer. I became his Ph.D. student after he returned to the Parkes Observatory from California, and I helped in the construction of the Parkes interferometer. This consisted of a 60-ft dish connected to the existing 210-ft dish by a flexible cable trailing from the 60-footer. The interferometer was used to observe continuously at 467 and 1401 MHz while the 60-ft dish was pulled along a track. The wisdom of the design is illustrated by comparing observations of Pictor A made at Parkes and at Owens Valley.