How does the Very Large Array combine 27 radio dishes to make detailed images?

The Very Large Array (VLA) achieves its high-resolution imaging through a technique known as aperture synthesis. By using 27 independent parabolic dishes arranged in a Y-shaped pattern, the system simulates a single, massive telescope.123

The process works as follows:

• Interferometry: As a radio interferometer, the VLA captures radio waves from astronomical objects at multiple locations simultaneously. Because the waves reach each dish at slightly different times, the system uses variable-delay mechanisms to compensate for these differences.3
• Signal Integration: The signals recorded by the 27 antennas are integrated by a computer. This allows the waves to interfere with one another, creating a combined signal that provides a resolving power equivalent to a single dish up to 36 km (22 miles) in diameter.23
• Configuration: The dishes can be moved along rails to change their spacing, which alters the array's resolution and allows astronomers to tailor the instrument to specific observations.23