### Implementation issues

The new implementation of IMAGER and in particular of the UV_MAP and CLEAN commands uses most of the older code, but re-arranged such that ensembles of contiguous channels (“chunks”) are treated at once and share the same synthesized beam. Deconvolution with CLEAN then proceeds by using the synthesized beam with the appropriate frequency for each channel. The user can control the “chunk” size, and hence the precision of the process given the desired field of view.

As a result of the new concept, beams (whether primary or synthesized) can be 4-D arrays, as they may depend on Frequency and Field.