Documentation for WebbPSF

WebbPSF is a Python package that computes simulated point spread functions (PSFs) for NASA’s James Webb Space Telescope (JWST) and Nancy Grace Roman Space Telescope (formerly WFIRST). WebbPSF transforms models of telescope and instrument optical state into PSFs, taking into account detector pixel scales, rotations, filter profiles, and point source spectra. It is not a full optical model of JWST, but rather a tool for transforming optical path difference (OPD) maps, created with some other tool, into the resulting PSFs as observed with JWST’s or Roman’s instruments.

Sample PSFs for JWST’s instrument suite, all on the same angular scale and display stretch.

Sample PSFs for the filters in the Roman WFI.

Contributors: WebbPSF has been developed by Marshall Perrin, Shannon Osborne, Robel Geda, Joseph Long, Justin Otor, Jarron Leisenring, Neil Zimmerman, Keira Brooks, and Anand Sivaramakrishnan, with contributions from Marcio Meléndez Hernandez, Alden Jurling, Lauren Chambers, Ewan Douglas, Charles Lajoie, Megan Sosey, and Kathryn St.Laurent. We also are grateful to the contributors of the astropy-helpers and stsci package templates.

Getting Started with WebbPSF

See Using WebbPSF.

Quickstart Jupyter Notebook

This documentation is complemented by an Jupyter Notebook format quickstart tutorial. Downloading and running that notebook is a great way to get started using WebbPSF.

Note

Getting help: For help using or installing webbpsf, you can contact the STScI JWST Help Desk at jwsthelp.stsci.edu. Note that WebbPSF is included in the Astroconda python distribution, as well as being installable via standard Python packaging tools.

What’s new in the latest release?

Contents

• Introduction
• Requirements & Installation
• Release Notes
• Using WebbPSF
• JWST Instrument Model Details
• Visualizing the JWST Optical Budget
• JWST Using Wavefronts Measured On Orbit
• Plots of JWST Wavefronts Over Time
• Roman Instrument Model Details
• Using PSF Grids
• More Examples
• Overview of POPPY (Physical Optics Propagation in Python)

Advanced Usage

• Detailed API Reference
• Diagnostics & Troubleshooting
• Sampling Requirements for Numerical Accuracy
• Optimizing FFT Performance for PSF Computations with FFTW

Appendices and Reference

• Appendix: Available Optical Path Difference (OPD) files
• WebbPSF Multifield Model for OTE WFE
• Field Dependence in JWST
• Model usage in WebbPSF
• Appendix: Instrument Property References
• Developer Notes: Releasing a new version of WebbPSF

How to cite WebbPSF

In addition to this documentation, WebbPSF is described in the following references. Users of WebbPSF are encouraged to cite one of these.

• Perrin et al. 2014, “Updated point spread function simulations for JWST with WebbPSF”, Proc. SPIE. 9143,

• Perrin et al. 2012, “Simulating point spread functions for the James Webb Space Telescope with WebbPSF”, Proc SPIE 8842, and

• Perrin 2011, Improved PSF Simulations for JWST: Methods, Algorithms, and Validation, JWST Technical report JWST-STScI-002469.

In particular, the 2012 SPIE paper gives a broad overview, the 2014 SPIE paper presents comparisons to instrument cryotest data, and the Technical Report document describes in more detail the relevant optical physics, explains design decisions and motivation for WebbPSF’s architecture, and presents extensive validation tests demonstrating consistency between WebbPSF and other PSF simulation packages used throughout the JWST project.

• Index

• Search Page

Mailing List

If you would like to receive email announcements of future versions, please contact Marshall Perrin, or visit maillist.stsci.edu to subscribe yourself to the “webbpsf-users@maillist.stsci.edu” list.