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 of the simulator functionality to be exercised [#chromatic]_. .. highlight:: none The ``romanisim-make-image`` command line interface (CLI) has a number of arguments to support this functionality:: romanisim-make-image -h usage: romanisim-make-image [-h] [--bandpass BANDPASS] [--boresight] [--catalog CATALOG] [--config CONFIG] [--date DATE] [--level LEVEL] [--ma_table_number MA_TABLE_NUMBER] [--nobj NOBJ] [--previous PREVIOUS] [--radec RADEC RADEC] [--rng_seed RNG_SEED] [--roll ROLL] [--sca SCA] [--usecrds] [--psftype {None,epsf,galsim,stpsf}] [--webbpsf] [--stpsf] [--truncate TRUNCATE] [--pretend-spectral PRETEND_SPECTRAL] [--drop-extra-dq] [--scale-factor SCALE_FACTOR] [--extra-counts EXTRA_COUNTS [EXTRA_COUNTS ...]] filename Make a demo image. positional arguments: filename output image (asdf). {} and {bandpass} strings will be automatically populated with detector and bandpass information. options: -h, --help show this help message and exit --bandpass BANDPASS bandpass to simulate (default: F087) --boresight radec specifies location of boresight, not center of WFI. (default: False) --catalog CATALOG input catalog (ecsv) (default: None) --config CONFIG input parameter override file (yaml) (default: None) --date DATE UTC Date and Time of observation to simulate in ISOT format. (default: 2026-01-01T00:00:00.000) --level LEVEL 1 or 2, for L1 or L2 output (default: 2) --ma_table_number MA_TABLE_NUMBER --nobj NOBJ --previous PREVIOUS previous simulated file in chronological order used for persistence modeling. (default: None) --radec RADEC RADEC ra and dec (deg) (default: None) --rng_seed RNG_SEED --roll ROLL Position angle (North towards YIdl) measured at the V2Ref/V3Ref of the aperture used. (default: 0) --sca SCA SCA to simulate. Use -1 to generate images for all SCAs; include {} in filename for this mode to indicate where the detector number should be filled, e.g. l1_{}.asdf (default: 7) --usecrds Use CRDS references. (default: False) --psftype {None,epsf,galsim,stpsf} Type of PSF to use. If None and --usecrds, then "epsf" will be used otherwise "galsim" is used. (default: None) --webbpsf Use stpsf for PSF (deprecated, use `--psftype stpsf`) (default: False) --stpsf Use stpsf for PSF (deprecated, use `--psftype stpsf`) (default: False) --truncate TRUNCATE If set, truncate the MA table at given number of resultants. (default: None) --pretend-spectral PRETEND_SPECTRAL Pretend the image is spectral. exposure.type and instrument.element are updated to be grism / prism. (default: None) --drop-extra-dq Do not store the optional simulated dq array. (default: False) --scale-factor SCALE_FACTOR Velocity aberration-induced scale factor. If negative, use given time to calculated based on orbit ephemeris. (default: -1.0) --extra-counts EXTRA_COUNTS [EXTRA_COUNTS ...] An optional FITS file to read to get an array of counts to add into the simulated image.Useful for wrapping idealized images.If 2 arguments are sent in, then the second argument is assumed to be the HDU to use (default=0) (default: None) EXAMPLE: romanisim-make-image output_image.asdf Expected arguments controlling things like the input :doc:`here ` to simulate, the right ascension and declination of the telescope [#boresight]_, the :doc:`bandpass `, the Sensor Chip Assembly (SCA) to simulate, the level of the image to simulate (:doc:`L1 ` or :doc:`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, and is recommended. If ``--psftype`` has not been specified, the CRDS EPSF references will be used to determine PSFs. The ``--psftype=stpsf`` argument indicates that the `STPSF `_ package should be used to simulate the PSF. If either ``epsf`` or ``stpsf`` is used for ``--psftype``, chromatic PSF rendering is disabled. 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 :doc:`persistence ` modeling. The ``--extra-counts`` argument(s) allows the user to pass in a FITS file with an array of counts (not counts/time). If a second argument is passed, it is assumed to be the HDU number to read. This argument is useful to wrap idealized images into the Roman L1/L2 datamodel, including detector effects. You will probably want to set ``--nobj 0`` here to avoid simulating additional sources. We do not get any additional information/metadata from this file, so you will need to set other parameters (e.g. ``--bandpass``, ``--date``, ``--radec``, etc) appropriately to match the image you are wrapping. .. [#chromatic] An important exception is the chromatic PSF rendering and photon-shooting modes of GalSim; the current catalog format does not support chromatic PSF rendering, and just assumes that all sources are "gray" within a bandpass. .. [#boresight] This right ascension corresponds to either the location of the center of the WFI array or the telescope boresight, when the ``--boresight`` argument is specified.