The mosaic is not trimmed to the dimensions of a single frame. Thus the noise will be greater in the peripheral areas having received less exposure time. The full signal will be in the central ninth containing the main object. For each cycle of four, the recipe creates a mosaic, which has its bad pixels filled and is then added into a master mosaic of improving signal to noise. Uses the Starlink NDF format.
History is recorded within the data files.
The title of the data is propagated through intermediate files to the mosaic. Error propagation is not used.