Radio telescope. The Hanbury Brown radio interfer- ometer near Narrabri, New South Wales, Australia. The Hanbury Brown interferometer consists of six 22 metre diameter radio telescopes that are combined by a technique called aperture synthesis to simulate a giant telescope with a diameter of up to 6km. Five of the telescopes are mounted on a 3km track (seen here) and the sixth is located 3km further west. A computer combines the signals to create a very high resolution image, used to measure the angular size of stars. Radio astronomy requires much larger telescopes than optical astronomy because the wavelength of radio waves is far greater than that of visible light.