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James Webb Space Telescope

Set of three images

The program jwpsf models Point Spread Functions for the James Webb Space Telescope. It models monochromatic and broadband PSFs, optionally incorporating source spectra and filter functions. Source spectra, representing a range of stellar types, are included in the package plus a selection of idealized filter functions. It is relatively simple for the user to supply alternatives. A description of this software was presented at the 2006 SPIE meeting on Astronomical Telescopes and Instrumentation. The paper is available for download (584KB).

Please note that a larger set of JWST's observational modes may be simulated using the WebbPSF program instead of JWPSF. WebbPSF also provides updated instrumental properties and simulated wavefronts, an improved user interface, and other enhancements. Please see the WebbPSF pages for further details. For the subset of cases that can be simulated with both JWPSF and WebbPSF, both programs yield consistent results.

The software is written in Python and will run on most platforms, but requires the installation of Python and associated packages NumPy, Pyfits, and Matplotlib. Instructions (PDF) for installing all components are supplied here, and a copy is included with the software.

If you have any difficulty installing this software or associated packages you may obtain assistance by contacting the helpdesk at

Downloading jwpsf :

To download copies of jwpsf, simply use our form.

Running jwpsf :

Instructions for running jwpsf.

Version History.

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