Using WebbPSF via the Graphical User Interface

The WebbPSF GUI provides an easy interface to much, but not all, of the functionality of WebbPSF. (Many advanced settings in the class attributes and options structure for webbpsf.JWInstrument are not exposed in the GUI. The programming API is also much better suited for scripting calculations.)


The GUI is mostly not actively developed any more, and is not recommended for more than basic use cases. It’s a nice way to play around, but we encourage almost everyone to use the Python API as their primary way of interacting with WebbPSF. The GUI may be deprecated in a future release.

Using the Graphical Interface

Once you have installed WebbPSF, you should have the launcher script webbpsfgui available. (If not, verify that the WebbPSF installation directory is on your system $PATH.)

Alternatively, you may start the GUI from an interactive session:

>>> import matplotlib
>>> matplotlib.use('TkAgg')
>>> import webbpsf
>>> webbpsf.gui()
The main window of ``webbpsfgui`` when first launched.

Figure 1: The main window of webbpsfgui when first launched.

The main window is divided into three regions:

  • The top region allows control of the source spectral type and position. (Selecting a source spectral type requires installing the optional dependency pysynphot.)
  • The central, main region allows selection of instrument and configuration of instrument options. The options available here largely correspond to attributes of the webbpsf.JWInstrument classes.
  • The lower region contains options for the PSF calculation itself such as pixel sampling and wavelengths. These correspond to parameters of the webbpsf.JWInstrument.calc_psf() function call.

GUI Controls

The GUI buttons invoke actions as follows:

Compute PSF

This invokes a PSF calculation with the given options. Each wavelength will be displayed in turn as it is computed, and finally the summed broadband PSF. This resulting PSF is stored in memory for use by the next three buttons.

Display PSF

This button will redisplay the PSF if the window has closed or something else has been displayed.

PSF display

Display Profiles

This will display the PSF’s radial profile and encircled energy profile.

PSF radial profiles display

Save PSF As…

This will invoke a standard File Save dialog box allowing you to save your new PSF to a FITS file.

Display Optics

This will display a graphical representation of the optical train for the current instrument configuration.

Sample "Display Optics" results showing NIRCam coronagraphic optics.

More Options…

The ‘More Options…’ button on the toolbar will bring up a window that allows you to select options controlling the computation of the PSF (e.g. which Fourier transform algorithm is used) or display of the PSF (e.g. which color map to use).

Sample "More Options" dialog box.



Matplotlib Back End Issues

On macOS, some users have encountered problems running the GUI due to incompatibilities with Matplotlib backends. If you see a severe error when trying to start the gui, try switching the backend to “TkAgg” rather than the default “MacOSX”. This needs to be done immediately after starting IPython, prior to any attempt to use the GUI, and ideally before even importing webbpsf:

import matplotlib
import webbpsf