 Okay, I've now transferred all my files from the camera onto the computer and organized them into these four folders, bias frames, dark frames, flats, and lights. And now what I'm going to do is I'm going to open up the free program deep sky stacker, which you can download from the web. And then I'm just going to follow along here on the left hand side, starting with open picture files. And I'm going to start by opening up all of my lights. So I'm just going to go into the lights folder, click on one, and then press control A to select all of them and click open. Okay, they come in right here. You can see that we have a long list of light frames, but for some reason it says light frame zero. So that's just because by default it doesn't check them. So we're just going to click check all over here on the left hand side. And now we can see we have 992 light frames. I did take a thousand, but just looking through them a little bit on the camera, I noticed at least eight that had clouds or other problems like focus problems. So I've already deleted those and we have 992. And then I'm just going to add the calibration files that we took. So starting with dark files, we'll go into my darks folder here. Press control A, click open. So we've added 50 darks. Then I'm going to click on flat files, go into my flats folder again, press control A and open, 46 flats. And then finally click on offset slash bias files, go into my biases folder, press control A to select all and click open. And we brought in 74 bias files. So now that we have everything loaded, we can go down to this command that's highlighted in red right here that says register checked pictures. I'm just going to click into advanced and click compute the number of detected stars. It tells me 75 stars were detected. And usually what I do is I'm going to lower the threshold a little bit until that number gets up over 100. So at 14%, it got up to 116 stars. That sounds good. And you might have to keep lowering your threshold. You could lower it all the way down to 5% or something, but just you want at least probably 100 stars to match on. Okay, I'm going to leave automatic detection of hot pixels turned on. I'm going to check stack after registering and say select the best 95% of pictures and stack them. If you wanted to look through the quality of your different pictures before stacking them, you could uncheck that. And then it will give every picture a quality score and you can do some extra work based on that. But I'm going to leave that part out in this video just because this is going to be, I'm just trying to keep it as simple as possible. I would recommend clicking on recommended settings and just looking through this and make sure that there's nothing that stands out that you have to do. You want to make sure that all the settings are set and then you'll see that all these things show in green based on what's recommended. And that's it. Then we're going to go ahead and click OK. And it will go through this whole process of registering the pictures, meaning looking at the star patterns and matching them up so that all of the pictures are lined up in terms of the stars. And then once it's done that, it can stack them, meaning averaging them. And by averaging them, it pays attention to where the signal is in the picture. So the stars and the Andromeda Galaxy. But the noise will be more random from picture to picture. And so by applying what's called Kappa Sigma Clipping, we throw out that random noise because it's so inconsistent. So that's how stacking works. One other thing is because there's not much room left on my laptop here, I am using a temp folder on an external drive. So if you do need to do that, you just click into stacking parameters here and then you can pick an external drive or USB thumb drive to hold your temporary files folder because for this picture, it's going to be quite large. So I'm going to click OK. And tells me we're stacking a thousand pictures at one second each. So that's equivalent to about 16 minutes total exposure. We can see everything was taken at ISO 3200. And it tells me that this process will temporarily use 109 or close to 110 gigabytes on the D drive. And I only have 169 gigabytes free. So getting close there, but I have just enough free that that should work. So let's go ahead and click OK and let it do its thing here. This is going to take a long time. So I'm just going to probably leave it overnight and we'll check up on it in the morning. This estimated remaining time, that's just for the current process. So I don't feel like it's going to be done in four minutes. It's really going to take hours and hours to do all this since we're dealing with so many frames. So this three minutes is just to stack the bias frames. Then it goes through a bunch of different things because it creates masters for each calibration file. It calibrates all the lights, it lights, it registers all the lights, which takes a really long time and it stacks all the lights, which again takes a lot of time. So I'm just going to leave this. And then when it's all done, we'll pick up there. OK, it's finished. It actually took it almost 22 hours to complete this whole stacking process, calibration, registration and stacking. This is what you want to see when it's done, meaning it's going to be in a linear state, meaning that the picture should be mostly black. You might see a few little white spots. These are bright star cores, but you don't really want to see anything too bright at this point. If everything went correctly, it should look pretty black like this. And it does do an autosave file. So in your lights folder, you should find an autosave.tif. I will warn you that that's a 32 bit file. So if you are using older versions of Photoshop or GIMP that don't have 32 bit support, you may not want to use that file. Otherwise, it's fine to use. But just to be safe, I'm going to show you how to save off a 16 bit tif file under the processing section right here. You just go to save picture to file. Make sure that it said is save as type tif image, 16 bits per channel. We'll give it a name. I'm just going to call it m31-dss. And under options, you want this option to be selected. Embed adjustments in the saved image, but do not apply them. Compression, I leave set to none. And so I'm just going to save this to my desktop. Click save. Here it is. And so this is what I'm going to bring into my next step into the post processing program. I've moved over to my Mac, but you should be able to follow along no matter what operating system you're on because the GNU image manipulation program is cross platform. So I'm just going to open it up here and I'm running version 2.10, which is what I recommend or just whatever is the latest when you watch this. And I'm going to go to file open and open the DSS file, the one that we stacked so carefully. OK, there it is to zoom in and out. You can use the minus and plus keys on the keyboard. I'm going to go ahead and duplicate this. So I'm just going to right click and choose duplicate layer. And I'm just going to keep this one below it as a safety. For this one right above, I'm going to go ahead and rename that first stretch. And on the first stretch layer, I'm going to start by opening up a levels command. But before I do that, if you don't see histograms up here and over in the upper right, go to windows, dockable dialogues and just turn it on right there. And then I would suggest switching the histogram mode from value to RGB. And we'll refer back to this while we're using the levels. OK, now to open up levels, I'm going to go to colors in the menu up here at the top and go down to levels. All right. And I'm just going to position this so that I can see my histogram up here and the image over here. And what I'm going to do is I'm going to go over here and you see this bar that goes from black to white. This represents all of the information in the image from shadows to pure white areas. And you can see right now that most of the information is all the way over here on the left in a very linear state. And so by stretching it, we make the image less linear or nonlinear and bring all the information out here. And then we can actually see what we're working on. And so to do that, what I'm going to do is I'm going to take my mid tones slider, this arrow in the middle. And you have to sort of grab it by the very top of it. And I'm going to take that mid tones slider, this little arrow right in the middle, and I'm going to drag it over to the left here until the image looks something like this. If you're looking up here at the histogram, you can just try to get these peaks about to the first line here or so. OK, and then I'm going to go ahead and click OK. And now we can zoom in a little bit and see that here's the galaxy. Doesn't look like much yet, but we're going to keep stretching the image and by adding contrast by making the sky darker and the galaxy brighter, it will really start coming out from the background. So I'm going to do another stretch, just the exact same thing I did. Just open up colors levels and take that mid tone slider again and move it once again to the to the left. But this time I'm also going to take the shadow slider, this arrow over here on the far left and drag that a little bit to the right. So I just want to take the mid tone slider, move it to the left, take the shadow slider and move it to the right. And this is how we stretch out the image. You'll see that this histogram peak gets wider and wider as we add, as we stretch out the values and add more shadow information, more mid tones information and more highlights information. We're not literally adding more information. We're just exposing it by stretching the values, making the curve less linear. OK, so I'm going to go ahead and keep doing that a little bit. That looks good. Click OK. Now, the next thing is if we look up here at the histogram information now, you can see that we have some interesting things going on where the green, blue and red peaks are hitting at different spots. And what's happening then in the image is it doesn't look, the colors don't look quite right. They don't look very neutral. And so what we're going to do is try to even these out a little bit. Again, with that levels command, so I'm going to go to colors, levels. And this time, instead of just jumping right in here with the sliders, I'm going to change the channel first to blue. And I'm just going to take that blue shadow slider and do something like that with it. And you'll see that right away our blue peak jumps way down here. Then I'm going to do the same thing with green. I'm going to grab that shadow slider. And what I'm going to do is I'm going to look up here and I'm going to try to basically have the left edge of the green peak and the left edge of the blue peak line up, something like that. And then I'm going to do the same thing with red. I'm going to take the shadows slider for red and move it over. I'm just going to do this little by little until it's in the right spot here. There we go. All right, and I'll click OK. So now if I zoom back out, we can see this sky looks fairly neutral. It doesn't look overly red or overly green because we have basically lined up the color channels. Now, there is a bit more green information, which is why the galaxy especially still looks a little bit green, but we'll fix that a little bit later on. I'm going to do another levels stretch this time just with the value as the channel, meaning stretching all three at the same time, R, G and B. And at this point, I'm going to make a few small cosmetic changes. The first thing I'm going to do is I'm going to crop because I think that this image will look better a little bit zoomed in on the galaxy rather than this wide field. So I'm going to take my crop tool and I'm just going to draw out a crop keeping Andromeda centered something like that and hit Enter. I'll zoom back in. I'm just going to duplicate this first stretch layer. I'm going to right click on it and choose duplicate layer. And I'll call this saturation and to the saturation layer here, I'm going to go back up to colors. And this time, instead of choosing levels, I'm going to choose saturation and just apply something like a 1.5 boost. And at this point, what we can see and you can see it up here in the histogram display, too, but it's quite obvious right in the image as well is that green is a little bit dominant. So to this saturation layer, I'm going to open up a new curves adjustment under the colors menu. And I'm going to take the green channel and just. Take it down. So basically just make a point right in the middle and drag that down. And then I'm going to take a blue channel and drag it up in the middle, but drag it down in the shadows. So now the galaxy is coming out a little bit more. I'm going to maybe just do one more curves layer this time, not using individual color channels, but just doing an S curve right on all three color channels with the channel set to value. OK, and that's looking really nice. Now, one thing you may not have realized is that when you shoot Andromeda in the northern hemisphere, this is actually what Andromeda looks like with north up in the image, meaning the top of the image is pointing towards the Polestar, the Polaris. And so but in most images that you see of Andromeda, it's flipped the other way around. And I like it flipped the other way around probably just because I've seen it that way so many more times. And so I'm going to go ahead and flip it. To do that in the new image manipulation program, you go to tools, transform tools, rotate. And a little window opens up and you can just type in the angle that you want to change. So if you did 90, it would do 90 degrees clockwise. I'm going to do 180 to do a full flip and then click rotate. And then I can close that. OK, we're. Going right along here. One thing that I noticed now, though, is because I took out green out of the. The galaxy, the background sky is looking quite red now. And so I'm going to go ahead and just open up another curves. So I go to colors, curves. And I'm going to take a red curve and just take the black point. And move it over until that looks more neutral and then click OK. And at this point, this is what I would call just a very naturalistic DSLR picture of Andromeda. And so if you want more, just sort of a quick edit, you could stop right here and save it off and be done. But I'm going to push it a bit further just to really see what we could do with a little bit more manipulation. So to do that, I can't push it too much further just because of the noise levels and things without separating out the stars, the background and the galaxy. And it's much easier to work on the background and the galaxy if you remove the stars from the image completely. And luckily there is a free program called StarNet++ that will do this work for us using a machine learning model. So we're going to save off what we have here to use in StarNet++ and I'll also show you downloading the program. But to do that, we need a flattened image. But just in case I want to come back to this one, let's go ahead and save it as a XCF file. So I'll just save that to the desktop. That means we can go back into the GNU image manipulation program and keep working on it. And then I'm going to go to image, flatten image. And the reason we have to do this is if we look at the channels right now, you can see that there's an alpha channel. We don't want that alpha channel because it will confuse StarNet++, which only expects three channels, red, green and blue. So we're going to go ahead and flatten the image. It brings it down into one layer. And now if we look at channels, that alpha channel is gone. And now we can save it off as a 16 bit TIF file. We do that with the export command. So you do file, export, and I'm going to call this stars.tif. Click export. It'll ask me if I want to do any compression on the file. I don't. So I'm just going to leave that set to none and then click export again. And now we have the stars.tif file on our desktop and we can remove the stars in StarNet++ and save it to the desktop. Then what I'm going to do is I'm going to Google StarNet++. This is a standalone program that's useful for removing stars from astrophotography. And I'm going to download it from this source forage page. And if you go to files up here at the top and then go into version 1.1, they have a nice zip file for each main type of operating system. So since I'm on a Mac, I'm going to download the Mac version. OK, once that's downloaded, I'm just going to move the entire StarNet macOS folder onto my desktop here and open it up. And then I'm just going to open up this run RGB StarNet.sh file with a text editor. I'm just going to change these two file names, the first one being the input file. So we called that stars.tif. And then I'm going to change the output file to m31starless.tif. This number is the stride. And typically I use a lower stride when I'm at a lower focal length and a higher stride when I'm at a higher focal length. It starts at 128, but you can go down to 16. I'm going to change it to 64 for this image. And typically the lower the stride number, the longer the process takes. So if you wanted to see what will happen, if you run it quicker, you can leave it on the default 128. OK, then I just have to move this stars.tif into the same directory. OK, with that shell file edited like this and the stars.tif file in the same directory, we now just have to run this file from a terminal command. So I'm just going to open up terminal and we have to get into this folder. So the command for that is cd for change directory space. And then I'm just going to drag this folder over and hit Enter. And then we just want to run this command or this sorry, this shell script, which calls on the actual program. So to run it, all I have to do is just drag it over and hit Enter. And it starts running. It gives us a little information about the file. It tells us how many different tiles. It's going to break it, the image up into to analyze. That's what the stride number is. So the slower the stride number, the more tiles that will break the image up into and then the longer it will take. And then it gives us a percentage finished. So this will take some time. Probably 20 to 30 minutes on my laptop with an image this size. With that done, I'm going to go ahead and open that image, the starless image back up into the new image manipulation program with file open. Click on the m31starless.tif and click open. It opens that image up into a new tab. You can see that we have two tabs now up here at the top. This is our star image and this is our starless image. After we are done changing the levels and the saturation a little bit on the starless image, we'll add the stars back in. So to do that, we're going to first duplicate it, is what I always like to start doing. So I'm going to right click and choose duplicate layer and I'll just call this curves. And like the name suggests, we're going to do some curves work on it. So go to colors, curves. And the first thing that I want to do is just basically add an S curve. So an S curve, you just sort of take the the left side of the histogram peak here and bring it down a little bit and then you make a point on the right side and bring that up a bit. OK, and then I would like to see the galaxy saturated a bit more. So I'm going to go ahead and add some more saturation just with colors, saturation and I'll bring it up to 1.2 OK, that's looking good. I can see some of the blue in the outer parts now, but that also brought up the saturation globally. So we don't like how saturated the background is now. It really brought out all the noise and artifacts from removing the stars. So I want to de-saturate just the background and also darken it. And to do that, we have to do something a little bit complicated, which is create a mask and specifically a luminance mask, which will protect the galaxy. There's actually three galaxies here. You can see one, two, three will protect the galaxies, but would not protect the background. And so to do that, we're going to duplicate again. So I'll just duplicate the curves layer. Right click, duplicate, and I'll call this mask. And the first thing I'm going to do the mask is I'm going to completely de-saturate it. So I'm going to take out all the color to make it grayscale. We can just do that with, again, the saturation. Command and just take it all the way down to zero. And then I'm going to apply a levels command to this mask. So I'm just going to go to colors levels. And I'm just going to drag the shadow slider way over to make this part of the image dark and then take the mid-tone slider and bring that over like that and just keep playing around with that a little bit. Until we have a result, something like this. And then I'm just going to switch my foreground color to black, grab my paintbrush, make a nice big brush and just darken out these corners here. OK, so this mask is pretty good now. We can now work on applying it. Before I do that, though, I'm going to duplicate the curves layer again. So I'm going to right-click on it and choose duplicate layer and call this duplicated layer dsatbg, short for desaturate the background. And to that desaturate bg layer, I'm going to right-click and choose add a layer mask. And this is how we apply the mask that we just created to this new layer. We add the layer mask, click add. And then we want to make a copy of what is currently visible. So that we can paste it into here. So to do that, we're going to do edit, copy visible. I'm then going to turn off the visibility of that mask layer and right-click on the layer mask and choose show layer mask. This selects it and you can now see there's a green outline around it. And then we're going to paste in what we have. It comes in as a floating selection and then you just click the anchor to anchor it down into the layer mask. OK, and since we want to desaturate the background with this layer mask, this is actually opposite of what we want, because right now white is selecting, black is protecting. And so if we applied the desaturation to this with this layer mask on, it would desaturate and drama to Galaxy and keep the background exactly the same. So we actually want to invert this, which is very easy to do. You just go to colors, invert. Great. OK, and now I can go ahead and right-click and turn off show layer mask. Click on the image part of the layer so that it's selected in white and we can now apply our desaturation with this layer mask applied and it should only apply to the background. So to do that, we go back to colors, go to saturation. And when we turn down the scale of the saturation, what you should see is that the Galaxy stays nice and saturated. But the background is losing all of that color noise. And I'm not going to bring it all the way down to zero. I think something like point two would look pretty good. OK, and then I'm going to on that same layer. I'm going to darken the background with colors, levels and just grab my black point, drag it over a little bit, grab my midpoint and drag that a little bit to the right as well. OK, very nice. So now we have something pretty good here. I'm going to go ahead and duplicate the curves layer. No, actually, I'm going to make a new from visible. So I'm going to just going to do layer new from visible. I'm going to add a layer mask to that one. Just do right click, add layer mask, add. And I'm going to once again apply this mask. The way we do that is just turn that layer back on. Click, edit, copy visible. Then you can turn the layer back off. Right click on the visible layer and choose show layer mask. It's now selected in green, then paste. Edit, paste and anchor it down. OK, so now we have the layer mask applied to this visible layer. I'll go ahead and turn that back off. At least the I'll go ahead and uncheck show layer mask. And I'm going to call this one set Galaxy for let's saturate the galaxy a little bit more. OK, and then we just do the colors, saturation and apply a little bit of a scale adjustment to the galaxy. And now really the only thing left to do is the center looks a little bit green when it should look a little bit warmer. So I'm just going to duplicate this whole set Galaxy layer and I'm going to show the layer mask. And I just want to paint in black everything but the core. So I want to paint out these arms because I don't want it to apply to that. I'm just going to use a nice soft brush like this. OK, and then we can turn the show layer mask back off. OK, I'm going to go up to colors color balance and I'm just going to subtly wait too much. Shift away from blues and greens a little bit in the center here just to warm that up a little bit. OK, so I'm going to turn the visibility of that off and on and you can see it went from a sort of cyan green to a warmer gold in the center there, which is what we want to see while the while the outer arms, which weren't part of that mask are still nice and blue. OK, this is looking good. We're ready now to add in our stars. So we're going to go back to this tab and do edit copy and edit paste. Actually, I'll do edit paste as new layer. Perfect. You can call this stars. And on that stars layer, you know, see right now it's just completely covering up all that work we did. So what we want actually to do is apply a screen blend mode, which takes away all the darker parts of the image and lets the brighter parts below shine through. So we'll just go up here to mode and change it to screen. And when we change it to screen, the whole image gets too bright. It really reveals a lot of noise, but also detail. And so we now want to apply a curves adjustment again. Instead of applying it to the stars layer, though, I want to make a new from visible layer. So I'm going to do layer new from visible. And on that one, I'm going to do colors, curves. And I'm going to start with a midpoint and bring the whole midpoint down. And then I'm going to take the shadow point and drag that over to the right, something like that. I'm noticing that there's a lot of red in the background. So I'm going to go ahead and open up a red curve and just take the shadow point and move it over to the right a little bit. You also hear this called a black point adjustment. So I'm just going to change the black point a little bit to take out some of that red, a little bit more even. There we go. OK, so that looks pretty good. The only thing is when we brought back in the stars layer, I see that the core is still pretty green there. So I'm going to make yet another new from visible. We'll call this one core. And I'm going to add a new layer mask to that core layer and initialize the layer mask to black. And then I'm just going to take a soft brush. I don't want it... Yeah, the hardness should be set to zero. I'm going to take down the opacity of it a little bit too. Take the opacity down to like 60. And I'm just going to brush in where it's too green here. And now I'm just going to apply another color balance adjustment under colors. All right. So now after the color balance, this is before very green, sort of a teal green, and then just taking that away with a color balance shift, the galaxy looks a lot more natural. And the only other thing I'm seeing here is this top corner. The top corners are a little bit red. So I'm just going to make once again a new from visible. So layer new from visible. I'll call this corners. I'm going to add a layer mask. Right click, add layer mask. I'm going to initialize it to black. Then I'm going to take a brush, take a nice big brush with like a 50% opacity. And I'm just going to get these corners here a little bit on the top. Okay. And I'm going to click back onto the visible layer and go to curves. And just take my red point a little bit and drop it over to the right until I don't see that red color noise up in the top anymore. And then speaking of noise. We can try to reduce it a little bit. We'll have to make once one more new from visible layer. I think this is the last one. We'll just call this nr for noise reduction. And in the new image manipulation program, the noise reduction is under filters enhance. And there's a noise reduction filter. And with a strength of four, it is taking two layers. And with a strength of four, it is taking too much out of the picture, I think. So I'm going to take that strength down to maybe one. I'll try two. And let me try zooming in on the picture. And just turning that preview off and on. Okay. I think two was even still a little bit too much for my taste. So I'm going to knock that all the way down to one and just apply noise reduction of one and click okay. And then we can see what it did just by turning it off and on. And I think the main thing it did is it took away a lot of the color noise in the background, which does look good. I think on that noise reduction layer, though, I'm just going to reset the black point one more time. Just because I noticed it's a little bit, still a little bit too much for me. So I'm just going to go to curves one more time and just take the black point over just a little bit. And that's it. We have now successfully edited our Andromeda image in the Deep Sky Stacker program, which is free and also GNU image manipulation program, which is also free and open source. So the only thing left to do is to save and export with whatever format you want to use. Of course, TIFF is good for long-term storage, but for saving for the web or for social media, PNG or JPEG would be better. So I'm going to use JPEG just by typing in m31.jpg and clicking export. It gives me some options. I'm just going to do full quality. Okay, and here is our final result. It does look a little bit noisy still, so maybe I was a little bit too hesitant to apply noise reduction. Maybe we should have increased that a little bit or not pushed it quite this far. But I do think it shows you what you can do with just a DSLR and a tripod and a lens using free programs to process your image. So hopefully this was helpful for you. You can always leave comments with suggestions, and if you want to support this channel, please consider subscribing, liking this video, leaving comments, and I also have a Patreon that starts at just $1 a month. Until next time, this has been Nico Carver from NebulaFotos.com. Clear skies. Thanks for watching.