Plateau de Bure interferometer - 2550m.
Consists of nine antennas the interferometer achieves high-resolution observations using a cluster of comparatively small telescopes rather than a single large telescope. In practical terms it is capable of synthesizing a telescope with a diameter of 760 meters.
The antennas are synchronized to move together enabling them to track the same source. The rotation of the earth, which slowly turns the antennas with respect to the source, enables step-by-step scanning of the source’s structure.