7 ms·

Thanks, but how is the sausage made then? Guess, that’s my main question. I get that the aquired data needs to be transformed in a way so we get an image that

Thanks, but how is the sausage made then? Guess, that’s my main question. I get that the aquired data needs to be transformed in a way so we get an image that depicts a reality we can visually process. I honestly thought there’s some tools in Nasa’s imaging group that, based on scientific rules, pumps out an image that is correct - seeing Photoshop in use left me wonder… I get that the investment needs to be “sold” too, would be sad though if we reached fashion-ad conduct for science… And don’t get me wrong: I am in awe and more than happy this thing finally gets put to use.

roywiggins 4y ago
I don't think there's a scientific definition of "correct" for these sorts of images. How would you even define correctness?
- whiteboardr 4y ago
  I might be wrong but in theory you know/see what elements are involved and burned in observed objects. Based on their distance, hence blue-/redshift, you could at least predict the visible colors we might perceive.
throwaway09223 4y ago
No, there's none of that. These pictures aren't being used for any kind of science. They're 100% PR pieces, made to look pretty - which is fine!
- april_22 4y ago
  Which makes me wonder how all these galaxies and nebulas would look like in real life. Would they look similar to how they colored it? Are those images maybe potraying a completely wrong reality?
  - Bud 4y ago
    Whose real life? Some of the aliens can see better than us. ;)
  - roywiggins 4y ago
    You can see different images of the Horsehead nebula and the differences in how colors are presented. They vary substantially, but not in any way that matters, at least to me on an aesthetic level. It's more like the difference between different white balances (which are, to some extent and in some contexts, arbitrary) in a terrestrial image. https://en.m.wikipedia.org/wiki/Horsehead_Nebula https://en.m.wikipedia.org/wiki/Horsehead_Nebula Maybe one or another of them is more "true to life" but since human eyes never evolved to view this stuff, there's no reason to think that the best and most informative view of an astronomical object is the visible light one.
  - wthomp 4y ago
    If you were to fly into these nebula in some kind of spaceship they wouldn't be any brighter than they appear in the night sky from Earth. They would just look way way bigger. The frustrating thing is that our eyes start to respond differently to colours when the light is really really faint. So we would probably perceive them as a grayish green haze. If the image was brightened artificiallythen we would see it as mostly red, with some browns and blues.
    - deleted 4y ago
      [deleted]
  - ceejayoz 4y ago
    Depends quite a lot on how you look. If you use an optical telescope to look at the Orion Nebula, you'll see it, but it'll appear pretty much grey. (No scope and it'll be what looks like a bright star, with perhaps a little bit of a blobby nature.) Hook a standard SLR camera up to the telescope and do a long exposure, though, and the reds and blues become readily apparent. Here's one I took with a standard camera and a 6" scope: https://www.instagram.com/p/CMtHMicBwvI/ https://www.instagram.com/p/CMtHMicBwvI/
  - 4y ago
- ghostpepper 4y ago
  I like to think that these cosmological structures are inherently beautiful the same way abstract mathematics is, and colorizing it is just a way to convey a sense of that beauty to most people who don't speak the language.
- creatonez 4y ago
  These are Webb's first science images, so published papers will come out of them. Of course, those papers will have additional data and analysis to go alongside it, but they absolutely are looking at details resolved in these specific images, processed in this specific way. So I'm not sure where the sentiment that these are just images for the public is coming from. That's certainly part of why these observations were made and processed this way, but there is science too.
  - throwaway09223 4y ago
    "but they absolutely are looking at details resolved in these specific images, processed in this specific way." I don't think you're correct. PR images from telescopes aren't new, so if you are correct then surely you'll be able to find papers based on older photoshopped images from Hubble. Are you able to find any?
    - creatonez 4y ago
      There are countless examples. The reason they composite the sensor layers in the first place is because they are trying to color code gases and dust for use by scientists. In some cases they are trying to highlight features that would be too dim otherwise. Here is an example of color-coded images from Hubble being used - https://iopscience.iop.org/article/10.1086/345911/pdf https://iopscience.iop.org/article/10.1086/345911/pdf - The same beautiful image used to get the public excited about space is used in Fig2 to locate where helium, nitrogen, and oxygen are in a planetary nebula. Even the 'Pillars of Creation' image was used for this sort of analysis, though it was less interesting than most images. "Beautiful" just happens to overlap with "highest contrast and most useful for study". JWST has more sensors than ever before, so it will be more colorful than ever before.
clint 4y ago
Photoshop is literally just a matrix transformation engine for data that is highly optimized for ease of use, extensibility, and making visual representations of that data.
- collinmanderson 4y ago
  Would be awesome to see if anyone can do machine learning using photoshop
semi-extrinsic 4y ago
There is no "correct" when you are shifting images from infrared to visible. But the "real science" part is probably done with a perceptually uniform color map. Or in the many cases where the image we see is actually a composite of many images taken with the narrow-band IR filter at different central wavelengths, the image might be presented with gaussians of different color corresponding to the different wavelength images. Or each wavelength is considered separately.
JacobThreeThree 4y ago
>so we get an image that depicts a reality we can visually process Since we can't visually process spectrums other than visible, there's no "correct" way to show the image.
dguest 4y ago
As others have hinted, the real science is going to be less pretty. For example, some algorithm might filter the raw images and extract objects matching some properties, fit them, and then run every reasonable manipulation of that filter to give the fit an error bar. Or they will compare spectra from many galaxies to understand their composition, again running every reasonable variation of the calculation to get some kind of uncertainty. The end science result will be a graph of some kind in a paper, but it costs very little extra to make these beautiful images on the side.
jacquesm 4y ago
> Thanks, but how is the sausage made then? I can't tell you because I wasn't looking over the shoulder of whoever made the image, but at a guess they started off from a black and white image, then turned it into an RGB image and change the various hues until relevant details became easier to see. The reason that that works is because a large scale structure has areas that emit at roughly the same intensity so you can bring these out by colorizing such a range with a gradient around a single hue. This is not an automated process because a computer would not know what we humans find 'interesting structures', if you could put that into some form of definition then you might be able to automate the process in the same way that black-and-white images are automatically colorized (which works, but which is sometimes hilariously wrong). As for the sausage, how it is made is interesting, how it tastes is from a PR perspective probably more interesting. And regardless you could argue that anything that differs from an utterly black square is 'not truthful'.
pkaye 4y ago
They do have some custom tools that are publicly available. I saw some videos in the past showing how they use those tools along with Photoshop to process images.
mensetmanusman 4y ago
Because light red shifts over time/expansion, you could color these towards blue until they cover parts of the human vision space to what they would look like on earth a billion years ago or so. In that case you could render the image differently depending on how many millions of years in the past you were interested in. I.e these used to be human “visible” on earth, but eventually their colors shifted beyond what we can perceive with our eyes.
- s1artibartfast 4y ago
  Many of these images are close and not redshifted.
sandgiant 4y ago
This is manly a demonstration of the imaging capabilities of JWST. Making actual sausage is a way longer, way more boring process. It depends on the science of course, but generally the sausage is made with specialized software that produces contour plots with error bars and what-have-you. The actual calculations will be done using just numbers, fitting models to data without any pretty pictures at all. This likely wouldn't have made #1 on HN without "pretty pictures" (this is what astronomers calls them). Photoshop is made for pretty pictures so it would be silly _not_ to use it. :)
Breza 4y ago
If you'd like to see how space telescope results look in research, you can check out published articles about Hubble.

roywiggins 4y ago

I don't think there's a scientific definition of "correct" for these sorts of images. How would you even define correctness?

whiteboardr 4y ago
I might be wrong but in theory you know/see what elements are involved and burned in observed objects. Based on their distance, hence blue-/redshift, you could at least predict the visible colors we might perceive.

throwaway09223 4y ago

No, there's none of that. These pictures aren't being used for any kind of science. They're 100% PR pieces, made to look pretty - which is fine!

april_22 4y ago
Which makes me wonder how all these galaxies and nebulas would look like in real life. Would they look similar to how they colored it? Are those images maybe potraying a completely wrong reality?
- Bud 4y ago
  Whose real life? Some of the aliens can see better than us. ;)
- roywiggins 4y ago
  You can see different images of the Horsehead nebula and the differences in how colors are presented. They vary substantially, but not in any way that matters, at least to me on an aesthetic level. It's more like the difference between different white balances (which are, to some extent and in some contexts, arbitrary) in a terrestrial image. https://en.m.wikipedia.org/wiki/Horsehead_Nebula https://en.m.wikipedia.org/wiki/Horsehead_Nebula Maybe one or another of them is more "true to life" but since human eyes never evolved to view this stuff, there's no reason to think that the best and most informative view of an astronomical object is the visible light one.
- wthomp 4y ago
  If you were to fly into these nebula in some kind of spaceship they wouldn't be any brighter than they appear in the night sky from Earth. They would just look way way bigger. The frustrating thing is that our eyes start to respond differently to colours when the light is really really faint. So we would probably perceive them as a grayish green haze. If the image was brightened artificiallythen we would see it as mostly red, with some browns and blues.
  - deleted 4y ago
    [deleted]
- ceejayoz 4y ago
  Depends quite a lot on how you look. If you use an optical telescope to look at the Orion Nebula, you'll see it, but it'll appear pretty much grey. (No scope and it'll be what looks like a bright star, with perhaps a little bit of a blobby nature.) Hook a standard SLR camera up to the telescope and do a long exposure, though, and the reds and blues become readily apparent. Here's one I took with a standard camera and a 6" scope: https://www.instagram.com/p/CMtHMicBwvI/ https://www.instagram.com/p/CMtHMicBwvI/
- 4y ago
ghostpepper 4y ago
I like to think that these cosmological structures are inherently beautiful the same way abstract mathematics is, and colorizing it is just a way to convey a sense of that beauty to most people who don't speak the language.
creatonez 4y ago
These are Webb's first science images, so published papers will come out of them. Of course, those papers will have additional data and analysis to go alongside it, but they absolutely are looking at details resolved in these specific images, processed in this specific way. So I'm not sure where the sentiment that these are just images for the public is coming from. That's certainly part of why these observations were made and processed this way, but there is science too.
- throwaway09223 4y ago
  "but they absolutely are looking at details resolved in these specific images, processed in this specific way." I don't think you're correct. PR images from telescopes aren't new, so if you are correct then surely you'll be able to find papers based on older photoshopped images from Hubble. Are you able to find any?
  - creatonez 4y ago
    There are countless examples. The reason they composite the sensor layers in the first place is because they are trying to color code gases and dust for use by scientists. In some cases they are trying to highlight features that would be too dim otherwise. Here is an example of color-coded images from Hubble being used - https://iopscience.iop.org/article/10.1086/345911/pdf https://iopscience.iop.org/article/10.1086/345911/pdf - The same beautiful image used to get the public excited about space is used in Fig2 to locate where helium, nitrogen, and oxygen are in a planetary nebula. Even the 'Pillars of Creation' image was used for this sort of analysis, though it was less interesting than most images. "Beautiful" just happens to overlap with "highest contrast and most useful for study". JWST has more sensors than ever before, so it will be more colorful than ever before.

clint 4y ago

Photoshop is literally just a matrix transformation engine for data that is highly optimized for ease of use, extensibility, and making visual representations of that data.

collinmanderson 4y ago
Would be awesome to see if anyone can do machine learning using photoshop

semi-extrinsic 4y ago

There is no "correct" when you are shifting images from infrared to visible. But the "real science" part is probably done with a perceptually uniform color map. Or in the many cases where the image we see is actually a composite of many images taken with the narrow-band IR filter at different central wavelengths, the image might be presented with gaussians of different color corresponding to the different wavelength images. Or each wavelength is considered separately.

JacobThreeThree 4y ago

>so we get an image that depicts a reality we can visually process Since we can't visually process spectrums other than visible, there's no "correct" way to show the image.

dguest 4y ago

As others have hinted, the real science is going to be less pretty. For example, some algorithm might filter the raw images and extract objects matching some properties, fit them, and then run every reasonable manipulation of that filter to give the fit an error bar. Or they will compare spectra from many galaxies to understand their composition, again running every reasonable variation of the calculation to get some kind of uncertainty. The end science result will be a graph of some kind in a paper, but it costs very little extra to make these beautiful images on the side.

jacquesm 4y ago

> Thanks, but how is the sausage made then? I can't tell you because I wasn't looking over the shoulder of whoever made the image, but at a guess they started off from a black and white image, then turned it into an RGB image and change the various hues until relevant details became easier to see. The reason that that works is because a large scale structure has areas that emit at roughly the same intensity so you can bring these out by colorizing such a range with a gradient around a single hue. This is not an automated process because a computer would not know what we humans find 'interesting structures', if you could put that into some form of definition then you might be able to automate the process in the same way that black-and-white images are automatically colorized (which works, but which is sometimes hilariously wrong). As for the sausage, how it is made is interesting, how it tastes is from a PR perspective probably more interesting. And regardless you could argue that anything that differs from an utterly black square is 'not truthful'.

pkaye 4y ago

They do have some custom tools that are publicly available. I saw some videos in the past showing how they use those tools along with Photoshop to process images.

mensetmanusman 4y ago

Because light red shifts over time/expansion, you could color these towards blue until they cover parts of the human vision space to what they would look like on earth a billion years ago or so. In that case you could render the image differently depending on how many millions of years in the past you were interested in. I.e these used to be human “visible” on earth, but eventually their colors shifted beyond what we can perceive with our eyes.

s1artibartfast 4y ago
Many of these images are close and not redshifted.

sandgiant 4y ago

This is manly a demonstration of the imaging capabilities of JWST. Making actual sausage is a way longer, way more boring process. It depends on the science of course, but generally the sausage is made with specialized software that produces contour plots with error bars and what-have-you. The actual calculations will be done using just numbers, fitting models to data without any pretty pictures at all. This likely wouldn't have made #1 on HN without "pretty pictures" (this is what astronomers calls them). Photoshop is made for pretty pictures so it would be silly _not_ to use it. :)

Breza 4y ago

If you'd like to see how space telescope results look in research, you can check out published articles about Hubble.