From CASA Guides
- simdata just calls clean, so you should refer to help clean for more information.
- psfmode serves as a switch. If you want to just calculate visibilities and not deconvolve, set psfmode="none"
- leave psfmode as is and set niter=0 if you want to make a dirty image but not clean.
- threshold, weighting, robust, uvtaper, stokes, niter control the cleaning.
- simdata's default clean parameters are not particularly aggressive and almost certainly not optimal for your application. I recommend that you run simdata and then clean the measurement set in various ways to determine the best results.