Wide-field imaging and deconvolution

We are often asked why the wide-field imaging and deconvolution steps are more difficult than their equivalent for single-field. The main answer is that doing wide-field observations with an interferometer is kind of paradoxical. Indeed, (sub)millimeter interferometers are before all tuned to get the best possible spatial resolution. A natural consequence is the lack of measurement of the low spatial frequencies which are extremely important in wide-field observations. Hence the paradox.

Progress in the design (ALMA was designed with wide-field imaging as a main goal) or in performances (NOEMA and the 30-m) has led to wide-field images being now customary. The tools have become much simpler and user-friendly (see below !) but because of its paradoxical nature, wide-field imaging with an interferometer implies a knowledgeable use of those tools.