A former aperture synthesis array at the Mullard Radio Astronomy Observatory, near Cambridge, England. It consisted of eight 13-m dishes, four fixed and four movable, on an east–west baseline 4.8 km long. When opened in 1972 it was originally known as the Five-Kilometre Telescope, but was renamed in 1989 in honour of M. Ryle. It was closed in 2006 and its dishes now form part of the Arcminute MicroKelvin Imager (AMI), an instrument to study the cosmic microwave background.