Running the simulation¶

The primary means by which we expect most users to make images is the command line interface:

romanisim-make-image out.asdf

The combination of romanisim-make-image and various user-generated input catalogs allows most simulator functionality to be exercised [1].

The romanisim-make-image CLI has a number of arguments to support this functionality:

romanisim-make-image -h
usage: romanisim-make-image [-h] [--catalog CATALOG] [--radec RADEC RADEC] [--bandpass BANDPASS]
                            [--sca SCA] [--usecrds] [--webbpsf] [--date DATE [DATE ...]]
                            [--level LEVEL] [--ma_table_number MA_TABLE_NUMBER] [--seed SEED]
                            [--nobj NOBJ] [--boresight] [--previous PREVIOUS]
                            filename

Make a demo image.

positional arguments:
  filename              output image (fits)

optional arguments:
  -h, --help            show this help message and exit
  --catalog CATALOG     input catalog (csv) (default: None)
  --radec RADEC RADEC   ra and dec (deg) (default: None)
  --bandpass BANDPASS   bandpass to simulate (default: F087)
  --sca SCA             SCA to simulate (default: 7)
  --usecrds             Use CRDS for distortion map (default: False)
  --webbpsf             Use webbpsf for PSF (default: False)
  --date DATE [DATE ...]
                        Date of observation to simulate: year month day hour minute second
                        microsecond (default: None)
  --level LEVEL         1 or 2, for L1 or L2 output (default: 2)
  --ma_table_number MA_TABLE_NUMBER
  --rng_seed SEED
  --nobj NOBJ
  --boresight           radec specifies location of boresight, not center of WFI. (default: False)
  --previous PREVIOUS   previous simulated file in chronological order used for persistence modeling.
                        (default: None)

EXAMPLE: romanisim-make-image output_image.fits

Expected arguments controlling things like the input here to simulate, the right ascension and declination of the telescope [2], the bandpass, the SCA to simulate, the level of the image to simulate (L1 or L2), the MA table to use, and the time of the observation.

Additional arguments control some details of the simulation. The --usecrds argument indicates that reference files should be pulled from the Roman CRDS server; this is the recommended option when CRDS is available. The --webbpsf argument indicates that the WebbPSF package should be used to simulate the PSF; note that this presently disables chromatic PSF rendering.

The --rng_seed argument specifies a seed to the random number generator, enabling reproducible results.

The --nobj argument is only used when a catalog is not specified, and controls the number of objects that are simulated in that case.

The previous argument specifies the previous simulated frame. This information is used to support persistence modeling.