7.2.2 Mosaicking

If the source has an angular extent large enough that multiple pointings are required, the central position of each FORCAST field must be specified, with due consideration of the desired overlap of the individual frames. Mosaicking can be performed in each of the three available observing modes, NMC, NPC, and C2NC2. A sample mosaic using C2NC2 mode is demonstrated in Figure 7-8. One should keep in mind that for fields requiring large chop amplitudes, the effects of coma may compromise the image severely when in symmetric chopping mode (NMC and NPC).