To use OYSTER for imaging simulations, first create a data set using the
`fakescans` procedure. This will create scans, for which one can compute
model values using `calcmodel` after reading a model file. `calcmodel`
will compute the complex visibilities (*scans.complexvis*) and squared
visibilities (*scans.vissqm*). If one wants to write this data into a FITS
file, nothing needs to be copied since the procedure `put_fits` uses
the complex visibilities to derive the FITS visibility variables
amplitude and phase. If noise is to be added to the visibilities, it should
be added to the real and imaginary parts of scans.complexvis.

The data can then be mapped in AIPS with or without using phase self-calibration.

Christian Hummel 2009-10-20