The Bure plateau millimetric interferometer was built between 1985 and 1988, when the astronomical observations began. The first six dishes were put into service between 1985 and 2002. The site now has eleven that can operate day and night, unlike optical observatories. These radio telescopes are mounted on rails of several hundred meters (2,493 ft / 760 m on the east-west axis and 1,207 ft / 368 m on the north-south axis) to allow varying their separation distance. To point at an object very high in the sky, they stand like giant pawns on a vast chessboard.