What describes the configuration of the Very Large Array?

• A. Circular array
• B. Linear array
• C. Y-shaped array
• D. Random arrangement

Answer: (C)

The main idea is how an interferometer’s antenna layout shapes the image you can produce. The Very Large Array uses a Y-shaped arrangement of its 27 dishes, sitting on three arms that meet near a central area. This distinctive layout is chosen because it gives a wide and well-distributed set of baselines as the Earth rotates, which translates into good coverage of spatial frequencies. That broad, even sampling—often called good uv-coverage—lets the array reconstruct images with high fidelity across a range of angular sizes, rather than having elongated or poorly sampled artifacts.

If the antennas formed a circle, a line, or were scattered randomly, the sampling of spatial frequencies would be less uniform in direction and scale, leading to weaker image quality or distortions. The Y shape strikes a balance: it provides diversity in baseline directions and lengths, improving the synthesized beam and image quality, and the array can be reconfigured along those arms to different extents (more compact or more extended) while preserving that effective Y layout.