Why can an array of smaller interferometers have a better angular resolution than one large interferometer?
To understand why an array of smaller interferometers can have a better angular resolution than one large interferometer, we need to delve into the concept of angular resolution and interferometry.
Angular resolution refers to the ability of an imaging system to distinguish between two closely spaced objects. In interferometry, it is related to the ability to resolve small details in astronomical observations. When observing distant objects in space, such as stars or galaxies, the angular resolution determines how well we can distinguish between them.
In an interferometer, multiple telescopes (or interferometric antennas) are used together to simulate a larger detector aperture. The signals received by these telescopes are combined, resulting in an interference pattern that provides high-resolution measurements.
Now let's consider the case of one large interferometer versus an array of smaller interferometers:
1. Single large interferometer: With a single large interferometer, there is a limit to the physical size of the antennas or telescopes that can be used. This size is often limited by practical constraints such as cost, engineering challenges, or the diameter of the largest available parabolic reflector. The maximum baseline (distance between antennas) achievable is limited, which in turn limits the angular resolution of the interferometer. The larger the baseline, the better the angular resolution.
2. Array of smaller interferometers: In an array of smaller interferometers, the individual antennas or telescopes are spaced much further apart than the size of a single antenna. This can be achieved by spreading out the smaller antennas over a larger area. By increasing the baseline between the telescopes in the array, the angular resolution improves. The combination of signals from these smaller interferometers provides a greater baseline and thus higher angular resolution compared to a single, larger interferometer.
In summary, an array of smaller interferometers can achieve better angular resolution than one large interferometer because the increased baseline between the individual telescopes in the array allows for more precise measurements and better resolution of fine details in astronomical observations.