Combined mosaic images and beam cube can be read in MAPPING as standard
images. The MAPPING program will automatically switch to mosaic mode when
a PRIMARY beam is read in using command
READ PRIMARY file.lobe
A logical variable, DO_MOSAIC, is set to indicate the mosaic mode
is activated. To switch back to normal cleaning, reset this logical variable
to NO.
The primary beam cube contains information about the threshold level for primary beams; this information is necessary to make a coherent deconvolution. Two additional variables are used for mosaic cleaning: the search level, SEARCH_W and the restoring level, RESTORE_W. This levels specify to which relative sensitivity level searching clean components and restoring the sky brightness should be performed. Since the noise increases at the mosaic edges, inversely proportionally to these levels, they should not be too low. However, the search level should be low enough to include all the emission; clean components searching is further limited by the support defined by command SUPPORT as for normal cleaning.
If necessary, confusing sources close to the mosaic edges should be removed in individual fields using MX before the final mosaic is built.
Note that, contrary to the standard clean which does not correct for primary beam attenuation, the mosaic clean produces sky brightness images.