Routine imaging of the radio Sun began in 1967 with the commissioning of the Culgoora Radioheliograph, which operated until 1986. A radioheliograph is simply an interferometer that is dedicated to observing the Sun. In addition to Culgoora, notable examples include the Clark Lake Radioheliograph, Nançay Radioheliograph, Nobeyama Radioheliograph, Gauribidanur Radioheliograph, Siberian Radioheliograph, and Chinese Spectral Radioheliograph. Additionally, interferometers that are used for other astrophysical observations can also be used to observe the Sun. General-purpose radio telescopes that also perform solar observations include the Very Large Array, Atacama Large Millimeter Array, Murchison Widefield Array, and Low-Frequency Array. The collage above shows antennas from several low-frequency radio telescopes used to observe the Sun.