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James Webb Space Telescope
PSF Simulation Tool: WebbPSF

Set of WebbPSF demo images

Simulated point spread functions for JWST can be produced using the WebbPSF package. This program supercedes and replaces the older jwpsf. A library of precomputed PSFs is available if you would like to download one or two instances, but running the software yourself provides much more flexibility.

What does WebbPSF do?

PSFs are computed based on a supplied library of optical path difference (OPD) files consistent with the JWST optical error budget, including wavefront errors in the Optical Telescope Element (OTE) and in each instrument. 10 independent statistical realizations are provided for each. Using these, WebbPSF computes observed PSFs assuming Fraunhofer (far-field) propagation. WebbPSF provides:

Limitations: The spectroscopy modes of NIRSpec and MIRI are not yet supported. Detector imperfections are likewise not included. The current OPD models do not support field-dependent wavefront error across the instrument FOVs. Future versions of WebbPSF and related software packages will address these issues.

Obtaining WebbPSF:

WebbPSF is written in Python and should run on any platform that supports numpy/scipy/matplotlib. About 900 MB disk space is required, mostly for the simulated OPD map library.

Installation instructions and download links.

Release notes.

Software Documentation:

WebbPSF documentation main page

Quick start

Scripting interface examples and graphical interface

WebbPSF Feedback:

WebbPSF was developed by Marshall Perrin, with contributions from other members of the Telescopes group at STScI. Please send any comments or suggestions to him at mperrin at stsci dot edu.