webbpsf_ext.webbpsf_ext_core.NIRCam_ext

class webbpsf_ext.webbpsf_ext_core.NIRCam_ext(filter=None, pupil_mask=None, image_mask=None, fov_pix=None, oversample=None, **kwargs)

Bases: webbpsf.webbpsf_core.NIRCam

NIRCam instrument PSF coefficients

Subclass of WebbPSF’s NIRCam class for generating polynomial coefficients to cache and quickly generate PSFs for arbitrary spectral types as well as WFE variations due to field-dependent OPDs and telescope thermal drifts.

Parameters

• filter (str) – Name of input filter.

• pupil_mask (str, None) – Pupil elements such as grisms or lyot stops (default: None).

• image_mask (str, None) – Specify which coronagraphic occulter (default: None).

• fov_pix (int) – Size of the PSF FoV in pixels (real SW or LW pixels). The defaults depend on the type of observation. Odd number place the PSF on the center of the pixel, whereas an even number centers it on the “crosshairs.”

• oversample (int) – Factor to oversample during WebbPSF calculations. Default 2 for coronagraphy and 4 otherwise.

__init__(filter=None, pupil_mask=None, image_mask=None, fov_pix=None, oversample=None, **kwargs)

Methods

__init__([filter, pupil_mask, image_mask, ...])
calc_datacube(wavelengths, *args, **kwargs)	Calculate a spectral datacube of PSFs
calc_psf([add_distortion, fov_pixels, ...])	Compute a PSF
calc_psf_from_coeff([sp, return_oversample, ...])	Create PSF image from polynomial coefficients
calc_psfs_grid([sp, wfe_drift, osamp, ...])	PSF grid across an instrumnet FoV
calc_psfs_sgd(xoff_asec, yoff_asec[, use_coeff])	Calculate small grid dither PSFs
display()	Display the currently configured optical system on screen
drift_opd(wfe_drift[, opd])	A quick method to drift the pupil OPD.
gen_mask_image([npix, pixelscale, ...])	Return an image representation of the focal plane mask attenuation.
gen_psf_coeff([bar_offset])	Generate PSF coefficients
gen_save_name([wfe_drift])	Generate save name for polynomial coefficient output file.
gen_wfedrift_coeff([force, save])	Fit WFE drift coefficients
gen_wfefield_coeff([force, save])	Fit WFE field-dependent coefficients
gen_wfemask_coeff([large_grid, force, save])	Fit WFE changes in mask position
get_bar_offset([narrow])	Obtain the value of the bar offset that would be passed through to PSF calculations for bar/wedge coronagraphic masks.
get_opd_file_full_path([opdfilename])	Return full path to the named OPD file.
get_opd_info([opd, pupil, HDUL_to_OTELM])	Parse out OPD information for a given OPD, which can be a file name, tuple (file,slice), HDUList, or OTE Linear Model.
get_optical_system([fft_oversample, ...])	Return an OpticalSystem instance corresponding to the instrument as currently configured.
interpolate_was_opd(array, newdim)	Interpolates an input 2D array to any given size.
load_was_opd(inputWasOpd[, size, save, filename])	Load and interpolate an OPD from the WAS.
psf_grid([num_psfs, all_detectors, save, ...])	Create a PSF library in the form of a grid of PSFs across the detector based on the specified instrument, filter, and detector.
set_position_from_aperture_name(aperture_name)	Set the simulated center point of the array based on a named SIAF aperture.
visualize_wfe_budget([slew_delta_time, ...])	Display a visual WFE budget showing the various terms that sum into the overall WFE for a given instrument

Attributes

LONG_WAVELENGTH_MAX
LONG_WAVELENGTH_MIN
ND_acq	Use Coronagraphic ND acquisition square?
SHORT_WAVELENGTH_MAX
SHORT_WAVELENGTH_MIN
aperturename	SIAF aperture name for detector pixel to sky coords transformations
bandpass	Return bandpass throughput
channel
coron_substrate	Include coronagraphic substrate material?
detector	Detector selected for simulated PSF
detector_list	Detectors on which the simulated PSF could lie
detector_position	The pixel position in (X, Y) on the detector, relative to the currently-selected SIAF aperture subarray.
fastaxis	Fast readout direction in sci coords
filter	Currently selected filter name (e.g.
filter_list	List of available filter names for this instrument
fov_pix
image_mask	Currently selected image plane mask, or None for direct imaging
is_coron	Observation with coronagraphic mask (incl Lyot stop)?
is_dark
is_grism
is_lyot	Is a Lyot mask in the pupil wheel?
module
name
ndeg
npsf	Number of wavelengths/PSFs to fit
options	A dictionary capable of storing other arbitrary options, for extensibility.
oversample
pixelscale	Detector pixel scale, in arcsec/pixel
pupil	Filename or fits.HDUList for JWST pupil mask.
pupil_mask	Currently selected Lyot pupil mask, or None for direct imaging
pupilopd	Filename or fits.HDUList for JWST pupil OPD.
quick	Perform quicker coeff calculation over limited bandwidth?
save_dir	Coefficient save directory
save_name	Coefficient file name
scaid	SCA ID (481, 482, .
siaf_ap	SIAF Aperture object
slowaxis	Slow readout direction in sci coords
telescope
wave_fit	Wavelength range to fit

property ND_acq

Use Coronagraphic ND acquisition square?

property aperturename

SIAF aperture name for detector pixel to sky coords transformations

property bandpass

Return bandpass throughput

calc_datacube(wavelengths, *args, **kwargs)

Calculate a spectral datacube of PSFs

Parameters

wavelengths (iterable of floats) – List or ndarray or tuple of floating point wavelengths in meters, such as you would supply in a call to calc_psf via the “monochromatic” option

calc_psf(add_distortion=None, fov_pixels=None, oversample=None, wfe_drift=None, coord_vals=None, coord_frame='tel', **kwargs)

Compute a PSF

Slight modification of inherent WebbPSF calc_psf function. If add_distortion, fov_pixels, and oversample are not specified, then we automatically use the associated attributes. Also, add ability to directly specify wfe_drift and coordinate offset values in the same fashion as calc_psf_from_coeff.

Notes

Additional PSF computation options (pupil shifts, source positions, jitter, …) may be set by configuring the .options dictionary attribute of this class.

Parameters

• sp (pysynphot.spectrum) – Source input spectrum. If not specified, the default is flat in phot lam. (equal number of photons per spectral bin).

• source (synphot.spectrum.SourceSpectrum or dict) – TODO: synphot not yet implemented in webbpsf_ext!!

• nlambda (int) – How many wavelengths to model for broadband? The default depends on how wide the filter is: (5,3,1) for types (W,M,N) respectively

• monochromatic (float, optional) – Setting this to a wavelength value (in meters) will compute a monochromatic PSF at that wavelength, overriding filter and nlambda settings.

• fov_arcsec (float) – field of view in arcsec. Default=5

• fov_pixels (int) – field of view in pixels. This is an alternative to fov_arcsec.

• outfile (string) – Filename to write. If None, then result is returned as an HDUList

• oversample, detector_oversample, fft_oversample (int) – How much to oversample. Default=4. By default the same factor is used for final output pixels and intermediate optical planes, but you may optionally use different factors if so desired.

• overwrite (bool) – overwrite output FITS file if it already exists?

• display (bool) – Whether to display the PSF when done or not.

• save_intermediates, return_intermediates (bool) – Options for saving to disk or returning to the calling function the intermediate optical planes during the propagation. This is useful if you want to e.g. examine the intensity in the Lyot plane for a coronagraphic propagation.

• normalize (string) – Desired normalization for output PSFs. See doc string for OpticalSystem.calc_psf. Default is to normalize the entrance pupil to have integrated total intensity = 1.

• add_distortion (bool) – If True, will add 2 new extensions to the PSF HDUlist object. The 2nd extension will be a distorted version of the over-sampled PSF and the 3rd extension will be a distorted version of the detector-sampled PSF.

• crop_psf (bool) – If True, when the PSF is rotated to match the detector’s rotation in the focal plane, the PSF will be cropped so the shape of the distorted PSF will match it’s undistorted counterpart. This will only be used for NIRCam, NIRISS, and FGS PSFs.

Keyword Arguments

• return_hdul (bool) – Return PSFs in an HDUList rather than set of arrays (default: True).

• return_oversample (bool) – Returns the oversampled version of the PSF instead of detector-sampled PSF. Only valid for reaturn_hdul=False, otherwise full HDUList returned. Default: True.

calc_psf_from_coeff(sp=None, return_oversample=True, wfe_drift=None, coord_vals=None, coord_frame='tel', coron_rescale=False, return_hdul=True, **kwargs)

Create PSF image from polynomial coefficients

Create a PSF image from instrument settings. The image is noiseless and doesn’t take into account any non-linearity or saturation effects, but is convolved with the instrument throughput. Pixel values are in counts/sec. The result is effectively an idealized slope image (no background).

Returns a single image or list of images if sp is a list of spectra. By default, it returns only the oversampled PSF, but setting return_oversample=False will instead return detector-sampled images.

Parameters

• sp (pysynphot.spectrum) – If not specified, the default is flat in phot lam (equal number of photons per spectral bin). The default is normalized to produce 1 count/sec within that bandpass, assuming the telescope collecting area and instrument bandpass. Coronagraphic PSFs will further decrease this due to the smaller pupil size and coronagraphic spot.

• return_oversample (bool) – Returns the oversampled version of the PSF instead of detector-sampled PSF. Default: True.

• wfe_drift (float or None) – Wavefront error drift amplitude in nm.

• coord_vals (tuple or None) – Coordinates (in arcsec or pixels) to calculate field-dependent PSF. If multiple values, then this should be an array ([xvals], [yvals]).

• coord_frame (str) –

  Type of input coordinates.

  • ‘tel’: arcsecs V2,V3

  • ‘sci’: pixels, in DMS axes orientation; aperture-dependent

  • ‘det’: pixels, in raw detector read out axes orientation

  • ‘idl’: arcsecs relative to aperture reference location.

• return_hdul (bool) – Return PSFs in an HDUList rather than set of arrays (default: True).

• coron_rescale (bool) – Rescale off-axis coronagraphic PSF to better match analytic prediction when source overlaps coronagraphic occulting mask. Primarily used for planetary companion PSFs.

calc_psfs_grid(sp=None, wfe_drift=0, osamp=1, npsf_per_full_fov=15, xsci_vals=None, ysci_vals=None, return_coords=None, use_coeff=True, **kwargs)

PSF grid across an instrumnet FoV

Create a grid of PSFs across instrument aperture FoV. By default, imaging observations will be for full detector FoV with regularly spaced grid. Coronagraphic observations will cover nominal coronagraphic mask region (usually 10s of arcsec) and will have logarithmically spaced values where appropriate.

Keyword Arguments

• sp (pysynphot.spectrum) – If not specified, the default is flat in phot lam (equal number of photons per wavelength bin). The default is normalized to produce 1 count/sec within that bandpass, assuming the telescope collecting area and instrument bandpass. Coronagraphic PSFs will further decrease this due to the smaller pupil size and suppression of coronagraphic mask. If set, then the resulting PSF image will be scaled to generate the total observed number of photons from the spectrum (ie., not scaled by unit response).

• wfe_drift (float) – Desired WFE drift value relative to default OPD.

• osamp (int) – Sampling of output PSF relative to detector sampling.

• npsf_per_full_fov (int) – Number of PSFs across one dimension of the instrument’s field of view. If a coronagraphic observation, then this is for the nominal coronagrahic field of view (20”x20”).

• xsci_vals (None or ndarray) – Option to pass a custom grid values along x-axis in ‘sci’ coords.

• ysci_vals (None or ndarray) – Option to pass a custom grid values along y-axis in ‘sci’ coords.

• return_coords (None or str) – Option to also return coordinate values in desired frame (‘det’, ‘sci’, ‘tel’, ‘idl’). Output is then xvals, yvals, hdul_psfs.

• use_coeff (bool) – If True, uses calc_psf_from_coeff, other WebbPSF’s built-in calc_psf.

• coron_rescale (bool) – Rescale off-axis coronagraphic PSF to better match analytic prediction when source overlaps coronagraphic occulting mask. Only valid for use_coeff=True.

calc_psfs_sgd(xoff_asec, yoff_asec, use_coeff=True, **kwargs)

Calculate small grid dither PSFs

Convenience function to calculation a series of SGD PSFs. This is essentially a wrapper around the calc_psf_from_coeff and calc_psf functions. Only valid for coronagraphic observations.

Parameters

• xoff_asec (float or array-like) – Offsets in x-direction (in ‘idl’ coordinates).

• yoff_asec (float or array-like) – Offsets in y-direction (in ‘idl’ coordinates).

• use_coeff (bool) – If True, uses calc_psf_from_coeff, other WebbPSF’s built-in calc_psf.

property coron_substrate

Include coronagraphic substrate material?

property detector

Detector selected for simulated PSF

Used in calculation of field-dependent aberrations. Must be selected from detectors in the detector_list attribute.

property detector_list

Detectors on which the simulated PSF could lie

property detector_position

The pixel position in (X, Y) on the detector, relative to the currently-selected SIAF aperture subarray. By default the SIAF aperture will correspond to the full-frame detector, so (X,Y) will in that case be absolute (X,Y) pixels on the detector. But if you select a subarray aperture name from the SIAF, then the (X,Y) are interpreted as (X,Y) within that subarray.

Please note, this is X,Y order - not a Pythonic y,x axes ordering.

display()

Display the currently configured optical system on screen

drift_opd(wfe_drift, opd=None)

A quick method to drift the pupil OPD. This function applies some WFE drift to input OPD file by breaking up the wfe_drift attribute into thermal, frill, and IEC components. If we want more realistic time evolution, then we should use the procedure in dev_utils/WebbPSF_OTE_LM.ipynb to create a time series of OPD maps, which can then be passed directly to create unique PSFs.

This outputs an OTE Linear Model. In order to update instrument class:

>>> opd_dict = inst.drift_opd()
>>> inst.pupilopd = opd_dict['opd']
>>> inst.pupil = opd_dict['opd']

property fastaxis

Fast readout direction in sci coords

property filter

Currently selected filter name (e.g. F200W)

gen_mask_image(npix=None, pixelscale=None, bar_offset=None, nd_squares=True)

Return an image representation of the focal plane mask attenuation. Output is in ‘sci’ coords orientation. If no image mask is present, then returns an array of all 1s. Mask is centered in image, while actual subarray readout has a slight offset.

Parameters

• npix (int) – Number of pixels in output image. If not set, then is automatically determined based on mask FoV and pixelscale

• pixelscale (float) – Size of output pixels in units of arcsec. If not specified, then selects oversample pixel scale.

gen_psf_coeff(bar_offset=0, **kwargs)

Generate PSF coefficients

Creates a set of coefficients that will generate simulated PSFs for any arbitrary wavelength. This function first simulates a number of evenly- spaced PSFs throughout the specified bandpass (or the full channel). An nth-degree polynomial is then fit to each oversampled pixel using a linear-least squares fitting routine. The final set of coefficients for each pixel is returned as an image cube. The returned set of coefficient are then used to produce PSF via calc_psf_from_coeff.

Useful for quickly generated imaging and dispersed PSFs for multiple spectral types.

Parameters

bar_offset (float) – For wedge masks, option to set the PSF position across the bar. In this framework, we generally set the default to 0, then use the gen_wfemask_coeff function to determine how the PSF changes along the wedge axis as well as perpendicular to the wedge. This allows for more arbitrary PSFs within the mask, including small grid dithers as well as variable PSFs for extended objects. Default: 0.

Keyword Arguments

• wfe_drift (float) – Wavefront error drift amplitude in nm.

• force (bool) – Forces a recalculation of PSF even if saved PSF exists. (default: False)

• save (bool) – Save the resulting PSF coefficients to a file? (default: True)

• nproc (bool or None) – Manual setting of number of processor cores to break up PSF calculation. If set to None, this is determined based on the requested PSF size, number of available memory, and hardware processor cores. The automatic calculation endeavors to leave a number of resources available to the user so as to not crash the user’s machine.

• return_results (bool) – By default, results are saved as object the attributes psf_coeff and psf_coeff_header. If return_results=True, results are instead returned as function outputs and will not be saved to the attributes. This is mostly used for successive coeff simulations to determine varying WFE drift or focal plane dependencies.

• return_extras (bool) – Additionally returns a dictionary of monochromatic PSFs images and their corresponding wavelengths for debugging purposes. Can be used with or without return_results. If return_results=False, then only this dictionary is returned, otherwise if return_results=False then returns everything as a 3-element tuple (psf_coeff, psf_coeff_header, extras_dict).

gen_save_name(wfe_drift=0)

Generate save name for polynomial coefficient output file.

gen_wfedrift_coeff(force=False, save=True, **kwargs)

Fit WFE drift coefficients

This function finds a relationship between PSF coefficients in the presence of WFE drift. For a series of WFE drift values, we generate corresponding PSF coefficients and fit a polynomial relationship to the residual values. This allows us to quickly modify a nominal set of PSF image coefficients to generate a new PSF where the WFE has drifted by some amplitude.

It’s Legendre’s all the way down…

Parameters

• force (bool) – Forces a recalculation of coefficients even if saved file exists. (default: False)

• save (bool) – Save the resulting PSF coefficients to a file? (default: True)

Keyword Arguments

• wfe_list (array-like) – A list of wavefront error drift values (nm) to calculate and fit. Default is [0,1,2,5,10,20,40], which covers the most-likely scenarios (1-5nm) while also covering a range of extreme drift values (10-40nm).

• return_results (bool) – By default, results are saved in self._psf_coeff_mod dictionary. If return_results=True, results are instead returned as function outputs and will not be saved to the dictionary attributes.

• return_raw (bool) – Normally, we return the relation between PSF coefficients as a function of position. Instead this returns (as function outputs) the raw values prior to fitting. Final results will not be saved to the dictionary attributes.

gen_wfefield_coeff(force=False, save=True, **kwargs)

Fit WFE field-dependent coefficients

Find a relationship between field position and PSF coefficients for non-coronagraphic observations and when include_si_wfe is enabled.

Parameters

• force (bool) – Forces a recalculation of coefficients even if saved file exists. (default: False)

• save (bool) – Save the resulting PSF coefficients to a file? (default: True)

Keyword Arguments

• return_results (bool) – By default, results are saved in self._psf_coeff_mod dictionary. If return_results=True, results are instead returned as function outputs and will not be saved to the dictionary attributes.

• return_raw (bool) – Normally, we return the relation between PSF coefficients as a function of position. Instead this returns (as function outputs) the raw values prior to fitting. Final results will not be saved to the dictionary attributes.

gen_wfemask_coeff(large_grid=False, force=False, save=True, **kwargs)

Fit WFE changes in mask position

For coronagraphic masks, slight changes in the PSF location relative to the image plane mask can substantially alter the PSF speckle pattern. This function generates a number of PSF coefficients at a variety of positions, then fits polynomials to the residuals to track how the PSF changes across the mask’s field of view. Special care is taken near the 10-20mas region in order to provide accurate sampling of the SGD offsets.

Parameters

• large_grid (bool) – Use a large number (high-density) of grid points to create coefficients. If True, then a higher fidelity PSF variations across the FoV, but could take hours to generate on the first pass. Setting to False allows for quicker coefficient creation with a smaller memory footprint, useful for testing and debugging.

• force (bool) – Forces a recalculation of coefficients even if saved file exists. (default: False)

• save (bool) – Save the resulting PSF coefficients to a file? (default: True)

Keyword Arguments

• return_results (bool) – By default, results are saved in self._psf_coeff_mod dictionary. If return_results=True, results are instead returned as function outputs and will not be saved to the dictionary attributes.

• return_raw (bool) – Normally, we return the relation between PSF coefficients as a function of position. Instead this returns (as function outputs) the raw values prior to fitting. Final results will not be saved to the dictionary attributes.

get_bar_offset(narrow=False)

Obtain the value of the bar offset that would be passed through to PSF calculations for bar/wedge coronagraphic masks.

get_opd_file_full_path(opdfilename=None)

Return full path to the named OPD file.

The OPD may be:

• a local or absolute path,

• or relative implicitly within an SI directory, e.g. $WEBBPSF_PATH/NIRCam/OPD

• or relative implicitly within $WEBBPSF_PATH

This function handles filling in the implicit path in the latter cases.

get_opd_info(opd=None, pupil=None, HDUL_to_OTELM=True)

Parse out OPD information for a given OPD, which can be a file name, tuple (file,slice), HDUList, or OTE Linear Model. Returns dictionary of some relevant information for logging purposes. The dictionary returns the OPD as an OTE LM by default.

This outputs an OTE Linear Model. In order to update instrument class:

>>> opd_dict = inst.get_opd_info()
>>> opd_new = opd_dict['pupilopd']
>>> inst.pupilopd = opd_new
>>> inst.pupil = opd_new

get_optical_system(fft_oversample=2, detector_oversample=None, fov_arcsec=2, fov_pixels=None, options=None)

Return an OpticalSystem instance corresponding to the instrument as currently configured.

When creating such an OpticalSystem, you must specify the parameters needed to define the desired sampling, specifically the oversampling and field of view.

Parameters

• fft_oversample (int) – Oversampling factor for intermediate plane calculations. Default is 2

• detector_oversample (int, optional) – By default the detector oversampling is equal to the intermediate calculation oversampling. If you wish to use a different value for the detector, set this parameter. Note that if you just want images at detector pixel resolution you will achieve higher fidelity by still using some oversampling (i.e. not setting oversample_detector=1) and instead rebinning down the oversampled data.

• fov_pixels (float) – Field of view in pixels. Overrides fov_arcsec if both set.

• fov_arcsec (float) – Field of view, in arcseconds. Default is 2

Returns

osys (poppy.OpticalSystem) – an optical system instance representing the desired configuration.

property image_mask

Currently selected image plane mask, or None for direct imaging

image_mask_list

List of available image_masks

include_ote_field_dependence

Should calculations include the Science Instrument internal WFE?

interpolate_was_opd(array, newdim)

Interpolates an input 2D array to any given size.

Parameters

• array (float) – input array to interpolate

• newdim (int) – new size of the 2D square array (newdim x newdim)

Returns

newopd (new array interpolated to (newdim x newdim))

property is_coron

Observation with coronagraphic mask (incl Lyot stop)?

property is_lyot

Is a Lyot mask in the pupil wheel?

load_was_opd(inputWasOpd, size=1024, save=False, filename='new_was_opd.fits')

Load and interpolate an OPD from the WAS.

Ingests a WAS OPD and interpolates it to the proper size for WebbPSF.

Parameters

• HDUlist_or_filename (string) – Either a fits.HDUList object or a filename of a FITS file on disk

• size (int, optional) – Desired size of the output OPD. Default is 1024.

• save (bool, optional) – Save the interpolated OPD if True. Default is False.

• filename (string, optional) – Filename of the output OPD, if ‘save’ is True. Default is ‘new_was_opd.fits’.

Returns

HDUlist (string) – fits.HDUList object of the interpolated OPD

property npsf

Number of wavelengths/PSFs to fit

psf_grid(num_psfs=16, all_detectors=True, save=False, outdir=None, outfile=None, overwrite=True, verbose=True, use_detsampled_psf=False, single_psf_centered=True, **kwargs)

Create a PSF library in the form of a grid of PSFs across the detector based on the specified instrument, filter, and detector. The output GriddedPSFModel object will contain a 3D array with axes [i, y, x] where i is the PSF position on the detector grid and (y,x) is the 2D PSF.

Parameters

• num_psfs (int) – The total number of fiducial PSFs to be created and saved in the files. This number must be a square number. Default is 16. E.g. num_psfs = 16 will create a 4x4 grid of fiducial PSFs.

• all_detectors (bool) – If True, run all detectors for the instrument. If False, run for the detector set in the instance. Default is True

• save (bool) – True/False boolean if you want to save your file. Default is False.

• outdir (str) – If “save” keyword is set to True, your file will be saved in the specified directory. Default of None will save it in the current directory

• outfile (str) – If “save” keyword is set to True, your file will be saved as {outfile}_det.fits. Default of None will save it as instr_det_filt_fovp#_samp#_npsf#.fits

• overwrite (bool) – True/False boolean to overwrite the output file if it already exists. Default is True.

• verbose (bool) – True/False boolean to print status updates. Default is True.

• use_detsampled_psf (bool) – If True, the grid of PSFs returned will be detector sampled (made by binning down the oversampled PSF). If False, the PSFs will be oversampled by the factor defined by the oversample/detector_oversample/fft_oversample keywords. Default is False. This is rarely needed - if uncertain, leave this alone.

• single_psf_centered (bool) – If num_psfs is set to 1, this defines where that psf is located. If True it will be the center of the detector, if False it will be the location defined in the WebbPSF attribute detector_position (reminder - detector_position is (x,y)). Default is True This is also rarely needed.

• **kwargs – Any extra arguments to pass the WebbPSF calc_psf() method call.

Returns

• gridmodel (photutils GriddedPSFModel object or list of objects) – Returns a GriddedPSFModel object or a list of objects if more than one configuration is specified (1 per instrument, detector, and filter) User also has the option to save the grid as a fits.HDUlist object.

• Use

• —-

• nir = webbpsf.NIRCam()

• nir.filter = “F090W”

• list_of_grids = nir.psf_grid(all_detectors=True, num_psfs=4)

• wfi = webbpsf.WFI()

• wfi.filter = “Z087”

• wfi.detector = “SCA02”

• grid = wfi.psf_grid(all_detectors=False, oversample=5, fov_pixels=101)

property pupil_mask

Currently selected Lyot pupil mask, or None for direct imaging

pupil_mask_list

List of available pupil_masks

property quick

Perform quicker coeff calculation over limited bandwidth?

property save_dir

Coefficient save directory

property save_name

Coefficient file name

property scaid

SCA ID (481, 482, … 489, 490)

set_position_from_aperture_name(aperture_name)

Set the simulated center point of the array based on a named SIAF aperture. This will adjust the detector and detector position attributes.

property siaf_ap

SIAF Aperture object

property slowaxis

Slow readout direction in sci coords

visualize_wfe_budget(slew_delta_time=<Quantity 14. d>, slew_case='EOL', ptt_only=False, verbose=True)

Display a visual WFE budget showing the various terms that sum into the overall WFE for a given instrument

Compares a WebbPSF instrument instance with the JWST optical budget for that instrument

Parameters

• inst (webbpsf.JWInstrument) – A JWST instrument instance

• slew_delta_time (astropy.Quantity time) – Time duration for thermal slew model

• slew_case (basestring) – ‘BOL’ or ‘EOL’ for beginning of life or end of life thermal slew model. EOL is about 3x higher amplitude

• ptt_only (bool) – When decomposing wavefront into controllable modes, use a PTT-only basis? The default is to use all controllable pose modes. (This is mostly a leftover debug option at this point, not likely useful in general)

• verbose (bool) – Be more verbose

property wave_fit

Wavelength range to fit