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Arrays Lose Large Scale Structure

As the diameter of a telescope increases, its resolution improves. The larger the diameter, the smaller the objects it can pick out. In contrast, telescopes with smaller diameters can resolve only larger objects. What does this mean for arrays?

Since arrays simulate one large telescope, their spatial resolution, depends on the distance between each pair of dishes. These distances, called baselines, are equivalent to the diameters of single-dish telescopes. Large baselines result in high spatial resolutions, while short baselines give low spatial resolutions.

Unfortunately no two dishes in an array can be placed closer together than the diameter of a single dish; otherwise they would overlap. This places a lower limit on the size of the baselines within an array, thereby constraining its ability to resolve large scale structures. The result: loss of information about the largest-scale features, as indicated by the dark regions in the image below.

Loss of Large-Scale Features in M82
JPEG Image (9K); Credit and Copyright

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