High resolution observations with a tracking radio interferometer

Previous workers have made use of the tracking technique as a means of varying the magnitude and position angle of the resolving power obtained with a fixed baseline interferometer. The present paper describes two extensions to this technique. The first refers to the equipment which has been developed to enable fringes to be obtained continuously over many hours while the second is an approach to a systematic method of interpreting the results in terms of models of the brightness distributions across the sources. The observations of a few sources with a 61 100 wavelength baseline are presented.