 This video is sponsored by Brilliant.org. Almost 30 years ago in 1995, an astronomer named Jeff Hester pointed the Hubble Space Telescope at the Eagle Nebula because he was interested in studying photo evaporation by looking at the nebula through different narrowband filters. And as part of his research process, he made a visualization, a full color image mapping the narrowband data according to the wavelength of each gas. And since S2 had the longest wavelength at 672 nanometers, that went into the red. H alpha at 656 nanometers went into the green. And O3 at 500 nanometers went into the blue channel. And he showed this resulting photo around to his colleagues, and they all agreed it was breathtaking. And of course, this became one of the most iconic space photos of all time and really helped boost the Hubble Space Telescope's reputation. Because it got good press and all the major newspapers and magazines all over the world. And I think NASA also did some brilliant marketing by calling it the Pillars of Creation, which is just a very cool name. It also popularized the use of mapping filtered data in chromatic order. This is sometimes called the Hubble Palate. Well, now, as you all know, there's a new space telescope, the JWST, which has captured its own version of the Pillars of Creation. But an infrared light. And just like the Hubble, the JWST's primary mission is of course science. It's figuring out the mysteries of the universe, looking at things like extremely red-shifted galaxies or analyzing the spectra of an exoplanet. But also just like Hubble, the JWST can produce amazing space photographs. And there are very talented staff at the Space Telescope Science Institute that make that happen because they edit the Stage 3 data for the JWST into these beautiful full-color visualizations that are then shared with the public. But what many people don't know is that you can download most of the data yourself from MAST, the Mikulsky Archive for Space Telescopes. I did a previous video on just this, but in that video I used the paid software PIX Insight and Photoshop to process. And I've always wanted to do a follow-up with completely free software. And so that's what I'm going to be showing today. My name is Nico Carver, and I invite you to edit along with me on the Pillars of Creation. Now the biggest challenges I ran into were very large downloads. Some of them were more than 2 gigabytes per filter. And as well as the different filters having different image dimensions and also not being perfectly aligned. So what I've done for this tutorial is I've taken care of all of the boring hard stuff for you. These three fits files at tinyurl.com slash jwst-pillars have already been resampled to the smallest size. So that allows us to have smaller file sizes and then they've already been aligned on the star patterns. So that's going to be a lot easier for you to work with the data. If you do want to explore the JWST data straight from MAST yourself in free software, there is good news because the I2D files are now open just fine in the new 1.2 version of SIRL. They didn't before, but now they do. And again, if you're new to all of this, it's going to be easier to start with the fits files I've already prepared because they've already been resampled and aligned. Anyways, let's get going with the tutorial. Okay, as I mentioned, all the software I'm going to be using is free, but let me just show you first where to get it. The first piece of software is called SIRIL, and it's available at sirl.org. It is cross-platform, so you can download it for whichever system you have. It is currently on version 1.2.0 beta 2, and I would recommend getting that most recent version for this. The next program is the GNU Image Manipulation Program, available at gimp.org. It is currently on version 2.10.34, and again, it's cross-platform. Three fits files that I've prepared and put on Google Drive here to follow along with the tutorial. And so to download these, just hover over one and click the download button and say download anyway, and do that for each one. They're each about 100 megabytes. That's about as small as I could make them. And like I said, some of these were over two gigabytes before, because they were just really big image dimensions, and also there was a lot of extra stuff included in the download that we don't need for this tutorial, which is just sort of about making a pretty picture, an aesthetic picture. Okay, those are now downloaded, the fits files. One thing interesting to keep in mind is Cyril only likes to open up fits files if they end in .fit, no s. So if you're downloading the original JWST data, I think it ends in .fits. So just, you can just redo the file extension and then they'll open up fine in Cyril. But again, these are the ones that I've already resized and aligned. Let's go ahead and open this with Cyril, just opening one at random. This one is the F187N filter. Okay, and you can see when you open it, it just looks completely black. And that's because we are in a linear display mode, meaning all of the data is bunched up over on the left-hand side and we're not seeing anything. So if you just go down here and you want to just sort of see what the data looks like, you can switch it to the autostretch mode. And there we go, isn't that beautiful? So that's the pillars of creation in a particular passband of infrared light. And this one is what we're going to use for blue, if I remember right, because you can see that it looks really strong, it looks like it has a really strong blue background. So very nice. The only thing that we have to do really before we bring it into the GNU image manipulation program and colorize it is stretch it. And stretching it just means taking it from this linear space to a non-linear space. So we apply what's called a non-linear stretch, meaning we're not just going to stretch all of the values linearly, like we're not just going to multiply them, we're going to apply basically a curve instead. And my favorite way to apply this curve is with the generalized hyperbolic stretch transformation. I know that's a mouthful, but we just call it GHS for short now. This is a really cool way to stretch your data with a really nice curve. And I'll show you the way that they recommend to use it and the way I use it for this first stretch. We're going to turn on the autostretch here and just find a dark part of the image in the sky background and just click and drag to make a little selection box there. And then over here, we're going to click on the eyedropper. And what it will do is it'll sample inside that selection box and tell you the value associated with the pixels in there. And that's what is called the symmetry point, where it's going to balance that curve and where it's going to add the most contrast to your picture. So now I'm going to switch it back to linear mode. And I'm going to increase this local stretch intensity, let's say to, I usually like somewhere around like 12 to 15 for this first stretch, something pretty high. And then start pulling up the stretch factor and you'll start seeing that the image starts to come alive. If we start seeing more and more of the image as we stretch more and more with this stretch factor. And one thing that they tell you in the instructions for this tool is to maybe initially do a stretch like this. So it's not showing much, but we can now see the data over here and go ahead and apply that. And then we'll move this selection box to something a little bit brighter, something a little bit more in right in the mid or lower section of this data right here. So we'll set the symmetry point again. And this time I'm not going to do quite an aggressive stretch intensity, maybe something like three. And we'll start stretching this out again. Okay. And at this point, I think that looks really good. I'm not, I don't want to at this point go too far. Something like this is fine. I like to keep it a little bit more subdued because we can always add more contrast later. But if we add too much contrast now, it's hard to sort of undo that contrast, if you know what I mean. So I like to just add a good amount of contrast now, but not too much. So something like this, I'm just saying something like this based on how it looks. And just from doing this enough times. Okay, I'll go ahead and apply that and go ahead and close this. And so that's all I'm going to do with this image at this point. So I want to go ahead and save it because I'm going to next open it up into the GNU image manipulation program. So I'll save it to my desktop as a TIFF file, just like that. Just so I remember, you know, this is a new file and TIFF usually works well. So I'll go ahead and click save. And then I'm just going to do that whole same process we just did with the other two files. And then let's open up our GNU image manipulation program. And I'll try open as layers and I'll open our three TIFF files. Okay, so we have our three TIFF files here. And remember, we're going to go in chromatic order with colorizing them. So what I'm going to do is actually put the smallest number, the 187 here on the bottom and the 335 in the middle and the 444 on top. And then I'll start and turn off the visibility of these first two and I'll start with this one. And I'm going to go to colors, oh, colorize. And it's grayed out, of course it is, because we haven't told the GNU image manipulation program that we want to work in an RGB color space. So we just have to go to the image menu and go down to mode and change it to RGB. Click convert and now it's in RGB. So now if we go to the colors menu and go down to colorize, it will colorize that layer. Okay, now, how do you pick the colors? This is a big question. If you go to the JWST processing guide website, I'm sure I'll link it in the description, there are documents about how they have mapped the colors. So you can just follow that. If you want to just follow what they did. If you want to play around and do it your own way. Again, chromatic order is the most common way to do this. So starting with this 187, I'm going to map it to blue. And then I'll turn on the next layer and I'll map this to a green. Okay, and with that done, you can see that the, right now the green layer is completely covering up the blue layer. The blue layer is hidden. And this is just the way that these Photoshop type programs work when you have the layers. Right now it's on the normal mode with opacity set to 100%. So it's completely covering up the layer below. If we change the blending mode from normal to something else, we can then get a blend of the two layers. So I just changed it to addition. And then let's do the same thing with this last layer. We'll turn that one on and go to colors, color eyes, and click on the color here and change it to a, actually I'm going to do a sort of orangey red. And again, I'll change the mode from normal to addition. Okay. And so with that, we have our first sort of full color version here. But if you don't like how these colors came out, here's the cool thing. You can go in here and just recolorize. So now that we have this all set up, I could just go back in and open up color eyes again and pick a different color and live. I can see what that change, you know, what's happening with that change. And what I always find really interesting about this colorizing process is just through the intensity of the color, you can get very different final results. So for instance, if I make this middle layer, the 335M filter, this intense green, right, I get this very green result. But watch what happens if I just desaturate that layer a little bit. Ooh, now that's looking really cool, right? It's bringing out some of those blues underneath and getting us a better mix with the reds to see a little bit more than we were before. And honestly, I can do this all day. You know, it's just a lot of fun for me just to play around with this until I get a result that I think is interesting. You know, I know others aren't like me and don't just like spending hours just sort of staring at colors. But for me, it's a lot of fun. So anyways, but let's just go over the basic process. You're going to colorize these three layers in some kind of chromatic order. So the bigger numbers are on the red side. The smaller numbers are going to be on your blue side. And then your median numbers are in between in the greens and yellows. After you've done some kind of colorization, you can make a new from visible layer. And on this visible layer, you can, which is just a combination of what you have so far, you can apply filters like unsharp mask or continue playing with the colors. So one way to do that is with this tool, the hue slash saturation tool. So for instance, if I pick cyan, I can change the hue of just the cyan in the picture make it a little bit more blue. I can make it more saturated, if that's what I'm going for. But be careful with this. It's very easy to abuse this tool and get what we call posturization. If you're not careful, because there's not enough. A lot of times there's not enough data in between two colors to really fill in if you're going wild with changing the hues. So this is a dangerous tool, but it can be fun for playing around with the colors. Okay, and then I'm going from one powerful tool that's easy to use right to another. If you go to colors curves, this is another very powerful tool that can completely change the look and color balance in your picture. Because what you can do is go and go up here to channel and just target, for instance, the red channel. And I think right now it's a little bit low on red, so I can take that red channel up like that. But of course, that's very easy then just to start washing out all this blue stuff that we got in our background. So what you can do is you can apply a curve to the red channel like I just did there, something like that. And then we could do the same in green. We could see if taking out a little bit of the green in the picture helps with the colors that we want to get. And I think this is starting to look really interesting. So you can see that just by playing around with these color channels, you can do a lot with playing around with the colors in the image. Now that we have everything balanced somewhat between the three filters. Okay, I basically ran out of time with this tutorial, so let's go ahead and call it a day. To share your creation here with the world, you can export it and the way that this program works, a new image manipulation program. You just type in the file ending you want. So I can just do combined.jpeg and click export to get a jpeg file that I could share online. So I'd be glad to see what you come up with. This has just been a quick tutorial to show that this is indeed possible with free software. And I hope that others will try it out. In this video, I just focused on the more artistic side of astrophotography, but I'm guessing if you're watching a video about data from a space telescope, you're into science and will love Brilliant. Brilliant.org offers interactive lessons on science and math so you can learn about physics, writing your own home in a really fun way through problem solving on their website. There are thousands of lessons already up and there are also new ones added every month. The lessons that I think you'll really like and that will really enhance your understanding of the JWST and telescopes in general are all in the course scientific thinking that I'm showing here on screen. So to try everything that Brilliant has to offer completely free for a full 30 days, visit brilliant.org slash nebula photos or click on the link in the description. The first 200 will get 20% off Brilliant's annual premium subscription after the free trial.