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How do the 27 dishes of the Very Large Array work together?

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Telescope Aerial view of the Keck Observatory's twin domes, which are opened to reveal the telescopes. Keck II is on the left and Keck I on the right.

The Very Large Array (VLA) functions as a radio interferometer, a system where multiple antennas work together to receive signals from the same astronomical object.12

The VLA consists of 27 parabolic dishes, each 25 meters in diameter, arranged in a Y-shaped pattern. Because radio waves reach these spaced antennas at slightly different times, the system uses a variable-delay mechanism to compensate for these differences. The recorded signals are then integrated by a computer, allowing the waves to interfere and reinforce one another.132

This process provides the VLA with a total collecting area equivalent to a single 130-meter antenna and an angular resolution comparable to a single dish up to 36 km in diameter. To adjust this resolution, the dishes can be moved independently along railroad tracks, changing the configuration of the array to suit the specific wavelength being observed.231