 Okay, welcome to part 2a on this series of imaging the Pleiades, or Messier 45. If you haven't seen part 1 yet, the link will be in the description, and in part 1 you can watch the first 46 minutes or so to get the whole picture of capturing the Pleiades and making the calibration files and everything like that, and learning the whole process of imaging. This part, though, 2a will be about using two free programs, DeepSkyStacker, and the GNU image manipulation program to process our astrophotography, and will be specifically processing the M45 tracked data today. Okay, now on my computer, this is a Windows laptop that I'm using so that I can use DeepSkyStacker, and I've moved my files, both my 60 lights and my calibration files to the computer so I can stack them using DeepSkyStacker. And I'm just going to show this once with the tracked results, but the only difference with the untracked results is you would need a lot more space on some hard drives to do this process, because if you're doing 2,000 lights and a few hundred calibration frames, that's going to take up many, many gigabytes of space, and then it's going to take up even more for the process, because DeepSkyStacker does use a lot of hard drive space while it's working and puts that all into a temp folder. And so what I do is I use external hard drives to manage all of this, because a lot of times, like on my laptop here, it has a SSD that's not very big, so I need to use external hard drives to make this process work, especially with the untracked results where I have so many files. But anyways, I've just organized my files, copied them off the camera's SD card into these folders, lights, which are again the actual pictures of the night sky, flats, which are the flat frames, which correct dust bunnies and optical problems like vignetting, darks, which match the lights in length and temperature, and bias, which are very, very short dark exposures. And I'm going to be using a free program you can download online called DeepSkyStacker. It is Windows only, but if you are a Mac or Linux user, I'll have future videos in this series which show programs for those systems. Let me find it here. There we go. Okay, and I guess I'm not on the latest version, but I doubt Moch has changed. This is what the interface should look like. If it doesn't look like this, if you're seeing something radically different, be aware that DeepSkyStacker is packaged with another program called DeepSkyStacker Live for live stacking. So, make sure that you're clicked into the regular DeepSkyStacker. It should say up here, DeepSkyStacker, four point something, and it should look just like this. Okay, anyways, let's go ahead and start and you basically just go down this left-hand side going through these different commands. The one thing that I like to do first before I do any of that is just set up my temporary folder. And I think this is under settings, stacking settings. Yes, here we go. So I think I've already actually set it up, but what you would want to do, and it will remember this setting if you've set it before, is click into settings and then it'll say temporary files folder and you just want to click on these three little dots and tell it where to put the temporary folder. So like I mentioned before, I don't have much space on the computer here. I only have six gigabytes. So the process of stacking would definitely fail. While on my external hard drive, I have 164 gigabytes free. And so I use that as my temporary folder. Okay, with that done, we can now load up our pictures. So we're just going to go up here into the upper left and click on open picture files. And my folder is on the desktop. And I'm going to start by bringing in all my lights. So I'm just going to click on one, press control a to select all and then click open. Okay, and it brings in all of our light frames here. But if we look right up here in this blue bar, it says light frames zero. And the reason for that is it only registers pictures that are checked. And for some reason, the first time you bring in some picture files, it doesn't check them. So I'm just going to click check all over here on the left. And somehow I thought it took 60, but it only took in 59. That's okay, close enough. I might have deleted one that was bad or something. So we have 59 light frames. And then we're going to add our dark files. We just go down the list here and go into the darks folder. And again, select all open. And now it starts checking them. So I have 49 dark frames, and then we'll bring in our flats. We're going to skip over dark flat files, so-called. These are files that would be darks that match your flat frames, but since our flat frames are very short, and we are using bias frames, we don't need dark flats. They would be to correct thermal noise in your flat frames if you were using very long darks, like with narrowband filters or something like that. So I'm going to skip over those. I am going to add bias files, though. Control A, click open. Okay, so we have everything loaded up here. 40 flats, 50 darks, 60 bias, 60 lights. Okay. And these numbers don't have to be exactly your numbers. Yours may be different. I would just always recommend at least 30 of each calibration file and as many light frames as possible. The other thing we can do is we can just quickly scroll through here and looking over in this far right-hand column, I can see that these all are registering as the same size, which is good. If you have any with incorrect geometry, you know what I mean, a different size, that might stop the process. Okay, this is all looking good. And I can also see that they're all CR2s, which is the Canon RAW file, which is what we want. Okay, that all looks good. So now we just have to check a few settings and then we can start the process and it just does its thing. And then we have a picture at the end. One thing I will point out here is you can look through your files right here. And so if you haven't already looked through your light frames, I would recommend looking through them and just making sure that they all have fairly round stars and that there aren't that have any like huge streaks or stars that look really bad or clouds or things like that. If you do find any with clouds or anything, you can just uncheck them and then it wouldn't include them in the stacked result. Okay, let's go ahead and click on register checked pictures over here on the left. You can see there's a link right there. And I'm going to click into advanced and click compute the number of detected stars. Okay, and it found 2088 stars. That's perfectly fine. I just want to show you if we take down the star detection threshold, then it will find more stars. And if we take up the star detection threshold, it will find fewer stars because it will treat smaller little things as noise. And so really it anywhere from a few percent to 20 percent, it really doesn't, I can't tell you exactly where to set this, but the point is you want it to be confident that it's finding enough stars. And I often get the question, well, even when I set my threshold to one percent, it says it's only finding three stars. If that's the case, then something went wrong with your capture because it should never have that much trouble finding stars. And the usual problems are that you weren't tracking or using the NPF rule correctly. So you have stars that aren't round or you were out of focus and then it can't find the stars because it finds the stars based on their star cores. And if it can't, if they're really out of focus and it can't find those star cores, I'm going to select the best 100 percent of pictures and stack them because I've already looked through these pictures. And I also want to get as close to a half an hour of data for each setup so we can make this a fair test. I am going to click stack after registering. And let's go into the recommended settings and look through these. These all look good. If it was if it was finding anything weird, and then I'm going to click on stacking parameters and just check this. Oh, this is another thing I hear people talk about. Well, why not enable one of these drizzles? It's going to make the picture bigger. I'm not going to get into what drizzling is, but I'm going to say if you if you don't know about drizzle, if you haven't read about it, don't check these because drizzle is a specific algorithm that you really need well-dithered data for it to work correctly. And so I would not check one of those unless you know what you're doing. OK, and then I just use sort of the recommended different stacking parameters through all of these. And one thing I'll note here is it will create an output file in the lights folder called autosave.tiff. You can certainly use that. It's a 32 bit tiff file. Or when you're all done, you can just click save picture to file and save it as a 16 bit tiff file, which will work with basically any processing software we use after this like Gimp or Photoshop. OK, this is all good. I'm going to go ahead and click OK and click OK again. It will give me a summary of everything. And this all looks good. And it tells me right down here how much space this process will temporarily use six point five gigabytes. Now, keep in mind that is going to be much, much higher with the unstacked process where we're stacking like some 1800 lights. So just keep that in mind that this is one advantage of using a tracker is your file sizes will be a lot more reasonable. OK, I'm going to click OK and let it start doing its thing. And so now it's very automated. It goes through all these different steps like creating calibration masters, calibrating your light frames, registering your light frames, stacking them in the end. What you have is one calibrated, registered, stacked light. So basically it's it's all of this stuff. All of these hundreds of pictures are used to make one final picture. And then we take that and bring it into the next program. OK, so we'll let it do its thing and then move on when it's done with that final auto save dot tiff. Or like I said, you can also save the tiff off as a 16 bit file with this save picture to file command over here. And then we'll bring it into the next program. OK, I have my output file from Deep Sky Stacker. I just saved it as a 16 bit tiff file here. And I'm just going to go ahead and open that up with the new image manipulation program. It asks if I want to convert to working sRGB and I do. OK, now we have our file in here and I can press the minus key to zoom out and the plus key or shift equals to zoom in. You can see that the picture is mostly black right now, except for a few saturated star cores. So the first thing that we're going to do is we're going to apply a stretch to the image. We do this by first duplicating the layer over here. So you can see I want to just keep this DSS dot tiff just in case we need to return to it. So I'm going to make a duplicate of this just by right clicking and choosing duplicate layer. And I'm going to rename this layer first stretch. And then what I'm going to do is I'm going to go up here to the colors menu and this is where we go to find many of the adjustments in the GNU image manipulation program. The adjustment that I'm going to use here is called levels. And basically what levels does is it has this sort of small histogram right here, but I also have a bigger histogram open over here, which you can get to just by clicking on histogram so I can see what I'm doing a little bit better. And I just take these the shadow slider in the mid tone slider and basically move them in on the histogram peak. Now it's the histogram peak right now in this linear form is so far right up against the left hand side that we have to start by doing a stretch with the mid tone slider. So I'm going to take that slider and I'm just going to grab it and grab and drag or click and drag and move it to the left like this. And you can see when I let go, it gives me a preview over here of what's happening, but I can also see on the histogram right here that that histogram peak has been moved over not quite half, but almost halfway over. So we're going to do this incrementally because now I can't really see what I'm doing here because it's so small. So I'm going to go ahead and click OK. And then we'll just open it right back up. So go to colors, levels again. And now we can see that it's out here. And this time I can grab my shadow slider and move that over. And so you can see the image is starting to take form. And we just do this a few times until it looks like we have brought up all of the data levels and that can really see the full extent of what we have here. Now a mistake that I see a lot of people making is maybe not stretching their image enough. So they maybe just will stop here and maybe just make, you know, the sky background black and think that that's all there is. But you really want to go ahead and fully stretch your data to see what's there. And this will bring out some noise, but it will also bring out all the signal you captured. And then you can make choices after you've really fully stretched it. So what I mean by that is we're going to do this a number of times. We're going to take the shadow slider and move it to the right and take the mid tone slider and move it aggressively to the left. So you're moving these two in on the histogram peak. And what's going to happen is you'll see that this histogram peak gets wider as more and more of the information is spread out and you're sort of adding dynamic range to the picture. The brightest brights will get brighter. The blackest blacks will get darker and you'll have a lot more information in between those two. Before all the information you can think of was sort of compressed down and then you're stretching it out. This is why we call it stretching. Okay. So we're going to go to levels again, do the same thing. Okay. And at this point you can see we have brought out a lot of the image. You can see that there's this faint dust sort of surrounding the main Pleiades star cluster. Out here extends up there and it also extends down into this corner down here. So that's good. Now I'm going to go ahead and just do one final levels here where I just set my black point by just taking the shadow slider and moving it over. And what I'd recommend at this point is don't try to set your black point too dark at this point. So you don't want it to actually be the sky to be actually be black. So do something like this where you can still see all of that dust and even the darkest points of the picture are not truly black. Okay. That looks good. Let's go ahead and make another duplicate. And from now on, I'm just probably going to do duplicates going by up here to layer and just choose new from visible, which is another way to basically make a new version just based on what you're seeing here and we can always rename it by saying that you want to edit the layer attributes and calling it something different. So I'm going to call this saturate and I'm going to go back to that colors menu. But this time instead of levels, I'm going to choose saturation and I'm just going to increase the scale here quite a bit. Okay. That looks good. So I just we can turn that layer off and on to see what we just did. You can see before and after. And one thing that you notice is that the Pleedy star cluster now looks nice and blue, but it also made the sky background quite blue, a darker blue. And so I'm going to now go back into colors and curves and I'm going to go up here to where it says channel value and change that to my blue curve and I'm going to reset the black point on the blue curve just by taking this little control point way over here in the bottom left corner and grabbing it, click and drag until it matches up with basically the start of this histogram peak. And you can see what that did is it reset the black point globally here. So the sky looks natural again. But if we turn this layer off and on, we can see what it did. So we could stop right here. This is actually a basic edit that I think looks really good. And if you were just going for a pretty sort of neutral processing of your data to sort of wanted to let the data sing for itself, you could stop here. I often sort of push things a little bit further. And one of the ways that I push things further is by using a method where we're going to take this image, remove all the stars from it using a program called star net plus plus, then we'll have this version with the stars and a version that is starless. And for in the version that is starless, we can play around with a curve a little bit, you know, making a little bit punchier, bringing out the dust and then we can add the stars back on top with a screen blend mode and the screen blend mode itself will accentuate anything, any faint dust and things in the picture. And so let's give that a shot. This is again, optional, but it will can it can really boost some of the faint details in your photograph. So to do this, we want to first make flatten the image because when it's not flattened, you have an alpha channel. So we're going to go to image, flatten image. We'll take everything and compress it down into one layer and then we'll export this as a tiff file. And I'm going to call it stars dot tiff. Save it to the desktop. Then what I'm going to do is I'm going to Google star net plus plus. 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 star net here. I'm going to go ahead and I put the folder that got downloaded onto my desktop. I'm going to go ahead and open that folder up and just drag my stars dot tiff file that I saved out of the GNU image manipulation program right into that folder. Then I'm going to open this run underscore RGB underscore star net dot SH with a text editor. You could do this with just like text edit or whatever. I'm going to use Adam is my preferred text editor. It opens up like this and then basically you just want to write in what the input file is right here. So for me, that's stars dot tiff. And then you can tell it what to call the output file, the starless version. So I'm going to call mine m 45 starless dot tiff. And then this is the stride number. And basically this is how many panels it's going to break down the image into or how fine those panels are going to be and a lower number will take longer, but it'll break it down into smaller pieces when it's going through and taking out the stars. And it's the default is 128. I usually use 64 for something like this for a lens based setup, but 128 seems to work well for telescope based setups. Okay. Anyways, I'm going to go ahead and save this file that I've edited. Then I'm going to go ahead and open up the terminal program. You can just click on this little magnifying glass and type in terminal. There we go. And I'm going to first tell it to go to this folder just by typing in CD, which means change directory space and then just dragging this folder over here and hitting enter. We're now inside that folder so I can execute commands in the folder. And so I'm just going to drag run RGB star net.sh right into there and hit enter. And it starts going now before we move off of star net, I just want to mention a few things. One star net uses TensorFlow. You your CPU may not support that in which case you just can't use star net unless you have a different computer. So it's something just to be aware of. I'm sorry if your computer doesn't work with star net. The other thing is I often get questions about, you know, technical questions about how this works. I'm showing right now the Mac way of doing it. My understanding is the only difference with Windows is you don't have a normal terminal program in Windows like this. You have the command prompt, which is a little bit different. But I think in Windows what you would do is just drag the TIFF file directly onto this one on this icon that's just RGB underscore star net plus plus and then it will start running the whole program just like this. Okay, hopefully that makes sense. One other thing to note about star net is that it is free and you can use it on any computer that offers the right instructions for the TensorFlow library, but it's also part of the program picks insight, which makes a little bit easier because you don't have to do all this stuff with terminal and, you know, editing a text file. So one thing to keep in mind is that in picks insight star net is now built in. You don't have to even do anything. It just comes with the latest installations of picks insight. Okay, I'm going to let this do its thing. You can see it's right now 5% finished. So it'll take a little bit of time to make the starless image when that's done. We'll bring it back into GIMP and keep working. Okay. Star net has finished taking out the stars. So let's go ahead and open that up into GIMP. Just file open. There it is. m45starless.tif and this is what it looks like. And now what I can do is I can increase the contrast and saturation on this a little bit. So I'm just going to use my colors commands. I'll do colors curves. And if I if I go really extreme here, you can see there's a lot of dust going on. I think that this weird dark line is some kind of artifact. I'm not sure what that's from. Um, I'm not going to go quite that extreme, but I'll do something like that and maybe we'll increase the saturation just a little bit. Okay. Good. And so now we're going to put this layer on top, the stars layer. So we'll do that by just doing edit copy visible. Go into this one and do edit paste in place. It comes in as a floating selection and we just want to click on the little green add a new layer button down here. And let's go ahead and rename this stars. And with the stars, we're going to go ahead and change the mode from normal in normal mode. You can see it's just covering up our starless version. We're going to change it to not hard mix. We're going to change it to screen. There we go. Okay. So that already looks pretty neat. Um, you can see the the dust is is really a lot accentuated over this one, but it also gave the overall picture a very bright blue sort of tone. So let's work with some curves and to do that, I'm going to make a new layer again. So we're going to go to layer new from visible. I'll call this one curves and like the name suggests, I'm going to go into colors curves. And I'm going to start with just the the value curve, which is is all the values in the picture and I'm just going to apply a basic S curve where you take the shadows and bring them down and take the highlights and keep those the same. So this is a very, very small S curve. You know, sometimes you'll see really dramatic ones like that or something, but I think that's a little garish. I don't I don't like how bright that made the picture. And so what I'm trying to do is just more bring the overall level down quite a bit, but keep the keep a little bit of punchiness in it by by just making another point here and keeping this part of the line pretty straight. Okay, cool. Now, I think it overall is a bit too blue, especially if I compare it to this image, sort of like a magenta blue. So really what it needs is you would think more green, but what I'm going to do instead is actually keep the green level where it's at and just remove blue and red in the shadows and I'll do that again with curves. So I'll go into curves again. This time I'll click where it says value under the channel and choose red and I'm just going to take that red black point and move it over a little bit. And I'm going to take the blue one and do the same thing, but with the blue one, I'm going to I'm also going to add a point up here, which is this part of the Pleiades and just make sure that that doesn't get too much blue taken out of it. Okay, something like that looks good. So I'm just going to compare again. Here's before you can see it's a good picture, but it's not super dynamic and then here's after and I think it's a lot more interesting a picture. One thing though it has done is maybe made the Pleiades a bit too bright or maybe not too bright, but just too a little bit washed out. And so if we wanted to, we could try to bring back a little bit of saturation in this core area of the Pleiades. And so I could do that by again doing a new layer from visible and to this one I'm going to add a selection. I'm just going to use my lasso tool and just sort of get the the bright core area of the Pleiades here. I'm going to go ahead and feather that quite aggressively. So you can feather by going to select feather and I'm going to feather it by a hundred pixels and then we can go ahead and saturate or let's make a layer mask from that. So let's just go ahead and do right click add layer mask and we're going to initially is the layer mask to the selection click add. Okay, and now we can get rid of the selection. Just click select none. So now everything that we do on this new visible layer is only applying to that central core area. So I'm just going to go ahead and rename this saturate core. Whoops to click back onto the layer. I was clicked onto the mask. So I'm going to click back on the layer and then I'm going to go to colors saturation and just by I just raise up the saturation a bit. Perfect. Okay, and I can see what I did here by clicking this off and on. There's before there's after I think it just adds a little bit even more punch. So here's the starting point of just basically a stretch and color correction and here's after the more extreme working with a starless layer screen blend mode and a bit of a punch to saturation and curves. So I think both processing styles are perfectly valid. I just usually go for like I think a little bit more extreme version here. Okay. Final thing I'm going to do here is just some savings so I can do file save to save it as an XCF file to open it back up in this program. But if I want to save for final, I can do file export as and this lets me save as Tiff for PNG or JPEG. So for putting on the web or sending my email, you do JPEG. You can either just type in JPEG up there or you can select it down here. I'll select it and I'll just call this M 45. Okay, save it to my desktop. Okay, and there is our final result out of deep sky stacker in the GNU image manipulation program using a sky watch or star adventurer Canon 200 millimeter lens and about 60 30 second frames stacked together. This has been Nico Carver from nebula photos dot com. I do have a patreon where you can support me if you like tutorials like this one and you're about to see all of the names of people who do support me over on patreon. I really think everyone who does because it keeps me going with this and and keeping to a good schedule and releasing new videos. So till next time, clear skies.