<p>Simple answer:  false-color does not in any way &quot;photoshop&quot; the original image information.  The term &quot;cleanup&quot; doesn't mean anything.  Quite probably multiple images were collected to reduce Poisson noise (both photon and sensor readout), but again that does nothing to manipulate the actual distribution of photons on the image plane.<br />
While diffraction spikes can be removed given solid knowledge of the telescope's mechanical construction, no matter what you do there will be some loss of fidelity.  (By way of comparison, you could look up methods for removing pure spherical defocus error in an image, for example)</p>

CC BY-SA 4.0
2022-07-14T08:04:57.260Z
Understood - but why not accept a small loss in fidelity as the price for improving the overall veracity of the image ? It’s not as if anyone is doing any science on these glossy composite public-relations images (as opposed to the underlying spectroscopic data from which they are constructed).
gandalf61
CC BY-SA 4.0
2024-11-21T18:54:03.807Z
Leaving in the iconic spikes lets us see pictures that are as close to the raw data as possible, which is important in a world where so much is algorithms and layers of fakery.

But for science, I imagine they run it through many kinds of de-convolution and other stuff. As well as rely more on spectra and less on images.
Kevin Kostlan
CC BY-SA 4.0
2024-11-21T22:08:31.540Z
@KevinKostlan  **all** images, be they from telescopes or SLR cameras,  film or solid-state arrays,  have been manipulated in several ways before we ever see them.  Spectral responsivity of the sensors or flim doesn't match the human eyeball, which in turn is wildly biased compared with the actual photon count per wavelength incoming.
Carl Witthoft
CC BY-SA 4.0
2022-07-13T12:09:22.440Z
2022-07-13T12:09:22.440Z
Carl Witthoft
<p>First released JWST images are amazing. However, given the amount of image processing, false colours, cleanup etc. that must have gone into these images, why not also remove or reduce the diffraction spikes on bright stars ? Since these are purely artefacts of the telescope construction and have nothing to do with what is being imaged.</p>

CC BY-SA 4.0
2022-07-13T09:49:37.170Z
"Why not?" Sounds easy but I'm quite sure it would be nearly impossible without leaving other even more distracting artifacts. (Have a look at answers to [What visual artifacts are expected from the JWST?](https://astronomy.stackexchange.com/q/11915/7982)) I think that answers to a new question like "What would be the challenges to removing or reducing the diffraction spikes on bright stars in space telescope images for public consumption? Has it ever been tried?" will be quite illuminating - perhaps that can be your follow-up question?
uhoh
CC BY-SA 4.0
2022-07-13T14:44:50.123Z
Space.SE duplicate: https://space.stackexchange.com/q/58624/20766
Rob
CC BY-SA 4.0
2022-07-13T16:54:12.610Z
What would you put in their place?
Dave Gremlin
CC BY-SA 4.0
2022-07-13T20:53:15.400Z
@Rob  In Stack Exchange "duplicate" as a very specific meaning and it does not relate to questions posted on other sites. Neither does cross-posting in this case. Calling it a duplicate may attract unnecessary negativity (down voting, closing) that otherwise might happen. Why not just say "answered in Space SE" or similar (e.g. "related in", and avoid using a term reserved for something different than this case?
uhoh
CC BY-SA 4.0
2022-07-13T21:03:15.187Z
@uhoh, only offering an existing answer; don't attribute additional meaning to the improvement.
Rob
CC BY-SA 4.0
2022-07-13T21:12:26.817Z
@Rob sure and that's great, but it's the use of "duplicate" that I'm mentioning. I've explained further in meta: [Should we avoid calling questions that have answers in other SE sites as "duplicate", which already has a specific and different meaning in SE?](https://astronomy.meta.stackexchange.com/q/867/7982)
uhoh
CC BY-SA 4.0
2022-07-13T21:35:06.437Z
@uhoh, using the words negative and cross-posting has a specific meaning and offers no improvement to the existing comments. --- It's common practice to point out additional answers and avoid duplication of your comments. --- This was brought up long before your new question: https://meta.stackexchange.com/a/4713/282094 https://meta.stackexchange.com/q/72733/282094 https://meta.stackexchange.com/q/329523/282094
Rob
CC BY-SA 4.0
2022-07-13T21:49:02.937Z
@Rob I've created the meta question to allow more space for this issue. I don't understand the reference to cross-posting unless you're suggesting gandalf61 here and BruceS there are the same user. "Duplicate" is a close reason. Let's not call questions that can't be closed as duplicated because they are not on the same site as duplicates, and questions asked by two different users as cross-posts. It can be confusing to new users and attract unnecessary and undeserved negativity.
uhoh
<james-webb-space-telescope><image-processing>
Why are diffraction spikes left in JWST public images?
gandalf61
# Why are diffraction spikes left in JWST public images?

(Asked by: username_0 on 2022-07-13)

First released JWST images are amazing. However, given the amount of image processing, false colours, cleanup etc. that must have gone into these images, why not also remove or reduce the diffraction spikes on bright stars ? Since these are purely artefacts of the telescope construction and have nothing to do with what is being imaged.

**Tags:** james-webb-space-telescope, image-processing
> **Comments:**
> **username_1**: "Why not?" Sounds easy but I'm quite sure it would be nearly impossible without leaving other even more distracting artifacts. (Have a look at answers to [What visual artifacts are expected from the JWST?](https://astronomy.stackexchange.com/q/11915/7982)) I think that answers to a new question like "What would be the challenges to removing or reducing the diffraction spikes on bright stars in space telescope images for public consumption? Has it ever been tried?" will be quite illuminating - perhaps that can be your follow-up question?  
> **username_2**: Space.SE duplicate: https://space.stackexchange.com/q/58624/20766  
> **username_3**: What would you put in their place?  
> **username_1**: @Rob  In Stack Exchange "duplicate" as a very specific meaning and it does not relate to questions posted on other sites. Neither does cross-posting in this case. Calling it a duplicate may attract unnecessary negativity (down voting, closing) that otherwise might happen. Why not just say "answered in Space SE" or similar (e.g. "related in", and avoid using a term reserved for something different than this case?  
> **username_2**: @uhoh, only offering an existing answer; don't attribute additional meaning to the improvement.  
> **username_1**: @Rob sure and that's great, but it's the use of "duplicate" that I'm mentioning. I've explained further in meta: [Should we avoid calling questions that have answers in other SE sites as "duplicate", which already has a specific and different meaning in SE?](https://astronomy.meta.stackexchange.com/q/867/7982)  
> **username_2**: @uhoh, using the words negative and cross-posting has a specific meaning and offers no improvement to the existing comments. --- It's common practice to point out additional answers and avoid duplication of your comments. --- This was brought up long before your new question: https://meta.stackexchange.com/a/4713/282094 https://meta.stackexchange.com/q/72733/282094 https://meta.stackexchange.com/q/329523/282094  
> **username_1**: @Rob I've created the meta question to allow more space for this issue. I don't understand the reference to cross-posting unless you're suggesting gandalf61 here and BruceS there are the same user. "Duplicate" is a close reason. Let's not call questions that can't be closed as duplicated because they are not on the same site as duplicates, and questions asked by two different users as cross-posts. It can be confusing to new users and attract unnecessary and undeserved negativity.  

---

## 1 answers

### Answer by username_4 on 2022-07-13. Score: 4

Simple answer: false-color does not in any way "photoshop" the original image information. The term "cleanup" doesn't mean anything. Quite probably multiple images were collected to reduce Poisson noise (both photon and sensor readout), but again that does nothing to manipulate the actual distribution of photons on the image plane.  
While diffraction spikes can be removed given solid knowledge of the telescope's mechanical construction, no matter what you do there will be some loss of fidelity. (By way of comparison, you could look up methods for removing pure spherical defocus error in an image, for example)

> **Comments:**
> **username_0**: Understood - but why not accept a small loss in fidelity as the price for improving the overall veracity of the image ? It’s not as if anyone is doing any science on these glossy composite public-relations images (as opposed to the underlying spectroscopic data from which they are constructed).  
> **username_5**: Leaving in the iconic spikes lets us see pictures that are as close to the raw data as possible, which is important in a world where so much is algorithms and layers of fakery.  But for science, I imagine they run it through many kinds of de-convolution and other stuff. As well as rely more on spectra and less on images.  
> **username_4**: @KevinKostlan  **all** images, be they from telescopes or SLR cameras,  film or solid-state arrays,  have been manipulated in several ways before we ever see them.  Spectral responsivity of the sensors or flim doesn't match the human eyeball, which in turn is wildly biased compared with the actual photon count per wavelength incoming.  

---

