<p>Are you asking about the PSF (point-spread function)?</p>
<p>There are some simulations &amp; basic images available as well as a downloadable package you can use to compute the PSF for a particular instrument and wavelength.  Since the telescope hasn't been fully assembled yet these are based on simulations.</p>
<ul>
<li><a href="https://www.stsci.edu/jwst/science-planning/proposal-planning-toolbox/psf-simulation-tool" rel="nofollow noreferrer">https://www.stsci.edu/jwst/science-planning/proposal-planning-toolbox/psf-simulation-tool</a></li>
<li><a href="https://stsci.app.box.com/v/jwst-simulated-psf-library" rel="nofollow noreferrer">https://stsci.app.box.com/v/jwst-simulated-psf-library</a></li>
</ul>

CC BY-SA 4.0
2016-02-19T19:32:10.200Z
2021-07-17T06:30:20.027Z
2021-07-17T06:30:20.027Z
Silenced Temporarily
<p>The JWST images will have various artifacts. I found a <a href="https://jwst-docs.stsci.edu/near-infrared-imager-and-slitless-spectrograph/niriss-predicted-performance/niriss-point-spread-functions" rel="noreferrer">web page</a> that summarises the situation for the <a href="https://jwst-docs.stsci.edu/near-infrared-imager-and-slitless-spectrograph/niriss-observing-modes/niriss-imaging" rel="noreferrer">Near Infrared Imager and Slitless Spectrograph</a> (NIRISS).</p>
<p>The image below (taken from that webpage) shows simulated point sources as they would appear on the detector (including the sampling by the 0.0656 arcsec pixels). The greyscale is on a logarithmic scale of brightness. Each postage stamp corresponds a 77x77 pixel region around the point source, imaged through <a href="https://jwst-docs.stsci.edu/near-infrared-imager-and-slitless-spectrograph/niriss-instrumentation/niriss-filters" rel="noreferrer">filters</a> at different wavelengths (identified by the code in the top left, where 090 corresponds to 0.9 <span class="math-container">$\mu$</span>m etc. and the W or M corresponds to wide-band or medium-band).</p>
<p><em>NIRISS simulated PSFs, with 0.0656 arcsec pixels</em>
<a href="https://i.sstatic.net/SPseN.png" rel="noreferrer"><img src="https://i.sstatic.net/SPseN.png" alt="JWST NIRISS PSFs" /></a></p>
<p>Then there is a <a href="https://jwst-docs.stsci.edu/near-infrared-camera/nircam-predicted-performance/nircam-point-spread-functions" rel="noreferrer">further web page</a> that gives the equivalent information for <a href="https://jwst-docs.stsci.edu/near-infrared-camera" rel="noreferrer">Near Infrared Camera</a> (NIRCam), which has a short-wavelength (SW) and long-wavelength (LW) channel, as well as several filters associated with each of these.</p>
<p><em>NIRCam SW simulated PSFs, with 0.031 arcsec pixels</em>
<a href="https://i.sstatic.net/YLhNV.jpg" rel="noreferrer"><img src="https://i.sstatic.net/YLhNV.jpg" alt="NIRCam  SW PSFs" /></a></p>
<p><em>NIRCam LW simulated PSFs, with 0.063 arcsec pixels</em>
<a href="https://i.sstatic.net/HD0Xi.jpg" rel="noreferrer"><img src="https://i.sstatic.net/HD0Xi.jpg" alt="NIRCam LW PSFs" /></a></p>

CC BY-SA 4.0
2021-07-17T10:45:11.633Z
2021-07-17T10:56:30.107Z
2021-07-17T10:56:30.107Z
ProfRob
<p>What visual artifacts should we expect from the images that will be released from the James Webb Space Telescope? Specifically, do we expect 3-pronged diffraction spikes (any preview how they would look?)? Do we expect any artifacts due to the honeycomb-like structure of the main mirror?</p>

CC BY-SA 3.0
2016-02-19T20:26:03.230Z
There won't be only mirror-like artifacts like A. Leistra stated, but additional every instrument will have their own artifacts, e.e. due to imperfect correction from flatfields, and also depending on the filterwheels/gratings used.
AtmosphericPrisonEscape
<observational-astronomy><telescope><space-telescope><james-webb-space-telescope>
What visual artifacts are expected from the JWST?
Oak
# What visual artifacts are expected from the JWST?

(Asked by: username_0 on 2015-09-26)

What visual artifacts should we expect from the images that will be released from the James Webb Space Telescope? Specifically, do we expect 3-pronged diffraction spikes (any preview how they would look?)? Do we expect any artifacts due to the honeycomb-like structure of the main mirror?

**Tags:** observational-astronomy, telescope, space-telescope, james-webb-space-telescope

> **Comments:**
> **username_1**: There won't be only mirror-like artifacts like A. Leistra stated, but additional every instrument will have their own artifacts, e.e. due to imperfect correction from flatfields, and also depending on the filterwheels/gratings used.  

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## 2 answers

### Answer by username_3 on 2021-07-17. Score: 6 | Accepted answer

The JWST images will have various artifacts. I found a [web page](https://jwst-docs.stsci.edu/near-infrared-imager-and-slitless-spectrograph/niriss-predicted-performance/niriss-point-spread-functions) that summarises the situation for the [Near Infrared Imager and Slitless Spectrograph](https://jwst-docs.stsci.edu/near-infrared-imager-and-slitless-spectrograph/niriss-observing-modes/niriss-imaging) (NIRISS).

The image below (taken from that webpage) shows simulated point sources as they would appear on the detector (including the sampling by the 0.0656 arcsec pixels). The greyscale is on a logarithmic scale of brightness. Each postage stamp corresponds a 77x77 pixel region around the point source, imaged through [filters](https://jwst-docs.stsci.edu/near-infrared-imager-and-slitless-spectrograph/niriss-instrumentation/niriss-filters) at different wavelengths (identified by the code in the top left, where 090 corresponds to 0.9 $\mu$m etc. and the W or M corresponds to wide-band or medium-band).

*NIRISS simulated PSFs, with 0.0656 arcsec pixels*
[![JWST NIRISS PSFs](https://i.sstatic.net/SPseN.png)](https://i.sstatic.net/SPseN.png)

Then there is a [further web page](https://jwst-docs.stsci.edu/near-infrared-camera/nircam-predicted-performance/nircam-point-spread-functions) that gives the equivalent information for [Near Infrared Camera](https://jwst-docs.stsci.edu/near-infrared-camera) (NIRCam), which has a short-wavelength (SW) and long-wavelength (LW) channel, as well as several filters associated with each of these.

*NIRCam SW simulated PSFs, with 0.031 arcsec pixels*
[![NIRCam  SW PSFs](https://i.sstatic.net/YLhNV.jpg)](https://i.sstatic.net/YLhNV.jpg)

*NIRCam LW simulated PSFs, with 0.063 arcsec pixels*
[![NIRCam LW PSFs](https://i.sstatic.net/HD0Xi.jpg)](https://i.sstatic.net/HD0Xi.jpg)


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### Answer by username_2 on 2016-02-19. Score: 5

Are you asking about the PSF (point-spread function)?

There are some simulations & basic images available as well as a downloadable package you can use to compute the PSF for a particular instrument and wavelength. Since the telescope hasn't been fully assembled yet these are based on simulations.

* <https://www.stsci.edu/jwst/science-planning/proposal-planning-toolbox/psf-simulation-tool>
* <https://stsci.app.box.com/v/jwst-simulated-psf-library>


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