Parabolic antennas 49 ft (15 m) in diameter observe the universe continuously, day and night, from the Bure plateau of the Dévoluy massif in the Hautes-Alpes. Built by IRAM (Institut de Radioastronomie Millimétrique) at an altitude of 8,366 ft (2,550 m), they form an interferometer capable of exploring the birth of stars in the heart of nebulae and the evolution of the main galaxies at the edge of the universe. The millimeter rays captured by each parabola are sent back to a secondary mirror supported by four branches. They are then focused towards a central focal point where the detectors stand. A correlator receiving the optical fibers carrying the radiation then creates interference fringes from which the scientific data are extracted.