Siril and GIMP - How to capture a galaxy with your DSLR, Part 2B

Hello! Welcome! This is Nico Carver from nebulaphotos.com this is part 2b in my series on capturing the pinwheel galaxy if you haven’t watched part one of the link is in the description and you can just watch the first hour and 22 minutes of that all about the capture process before switching over to this video which will show how to pre- process in a program called Siril which is a open source and free processing software that is available on all platforms basically imaginable it’s basically any Linux OS Mac OS or Windows so I’m gonna start here I just I’ve opened up the website Siril S I R I L dot org and just to show you the different download options so if you go up here to the download menu item and then scroll down the first thing you’ll notice is that it is free but they do accept donations via PayPal so you can donate it right there there’s a couple options right here at the start about downloading scripts and installation from sources just ignore these because if you keep going down then it says choose your OS and most of these packages will include both the program and some of the scripts so you can then click on any of these operating systems these the first seven here are all Linux operating systems and then we have Windows Mac OS and then a few others so I’m on Mac OS I’m going to click Mac OS and you have the option of installing via homebrew or you can just download the zip file and drag and drop the application to your Applications folder so that’s what I’m gonna do I’ll just mention here while we’re on this page though that if you’re on Windows you can just download an installer file right here the automatic installation or if you’re on one of these Linux os they are mostly available through very common package managers like the advanced package tool on Debian or on Ubuntu so it shouldn’t be hard to install just I wouldn’t recommend installing from source or anything like that I would just use one of these prepackaged things down here okay so we’ll get this all installed and then jump right in okay I’ve now installed the program and opened it up this is what it looks like when you open up the program the first thing that I found out about it is that you can do a lot of things manually just using these tabs up here or just like picks insight people have written scripts that allow you to speed up your processing by taking care a lot of the manual tasks for you more automatically so those are available under scripts and the first thing that I tried and there’s there’s more scripts available than this but these are the ones that it comes with initially the first thing that I tried was this DSLR pre-processing because that’s exactly what I want to use it for and if you just click on it instead of giving you any information or like letting you pick your files or something like that it just right away runs the script but this is sort of cool this is a little console here that shows you any errors of things like that and I can quickly see by reading through this little log of what the script did that it’s expecting for me to set a working directory because it couldn’t find anything in my pictures file which I guess pictures directory or folder which I guess was the default working directory that it was expecting then it the script failed and I know that because down here in blue it says script for DSLR color camera pre- processing needs four sets of raw images in the working directory within four directories biases flats darks and lights so what I’ve done is I’ve created a folder here on the desktop called m101 and inside that folder I’ve put diocese darks flats and lights and you can download all of this data from my website the link will be in the description so you can follow along with this or use your own data but the key thing here is if you’re using this script is you need a working directory or folder and then inside that folder you need four subfolders with these exact names lowercase diocese darks flats lights okay so how do we set the working directory what we do is we go down here to this blue button that says change dirt dot and if you hover over it the little tooltip tells me change current working directory so that’s what we want to do I’ll click on that button I’ll go to my desktop and click on m101 and click open and here in the log it says we change the current working directory to users Cepheus desktop m101 great so now let’s try running the script again so I’m just going to go up to scripts DSLR pre-processing and now what happens as you can see it’s immediately taking those files and doing something with them it’s reading in the bias files and gives you some information about them and it’s decoding them and right down here it gives me a little one-liner about what it’s doing right now so it is converting the raw bias files and then down here there’s a little progress bar and just like with deepskystacker if you’ve used that program this progress bar does not indicate the entire process but the current task so the current task is reading in and converting all of the bias files and so it’s almost done with that part of the process but as soon as it finishes that part it will move on to the next part of the script probably taking all those bias frames and putting them together then moving on to the darks and and so forth so this is going to take a while yep you can see what it’s doing now is it’s stacking the bias frames I know that because right there it says stack bias and so again this will take a while you can watch it as it goes if you want to or you can just leave it and come back I don’t know how long it’ll take maybe an hour or something like that maybe longer because we are working with a lot of files but anyways I’m gonna skip ahead in the video until this is all done and we’ll see what it puts out okay it is finished with the script and it tells us right down here at the bottom of the output log that the total execution time was 4 hours 41 minutes and 23 seconds so for 383 images so for 383 images with full calibration files and everything else that’s how long it took in Cyril I’m working on a MacBook Pro that’s a few years old ok so it finished but where is our image well if we look in the m101 folder you can see we now have a new file called result dot fit and the reason if you recognize this icon as the pics inside icon is because operating systems usually have something called the system viewer which basically that means what’s the default open command so on my system the the default for fits files is picks insight which is why we’re seeing that icon but we can also open it back up in Siril so if we go to the file menu and choose open this is something I find a little confusing why it’s grayed out here I feel like this should just be set to any files but for some reason it’s a too raw DSLR camera files have to click in here and find Fitz files and then you can select it and open it okay and Cyril opens up two windows we have this window which separates out the red green and blue channel and we have this window which is a composite RGB image and we know we’re not seeing anything right now because this is still in its linear state but if you go down here you can see there are a bunch of different options actually for a preview of what it would look like if you did stretch it with Auto stretch or arc science stretch or whatever so we can change it from linear to something else I’m just gonna choose Auto stretch okay and now you can see this bright green image the reason we have this black border along the bottom and on the right is because there was some drift through the night and Cyril doesn’t chop that off for you so it is all registered but it’s just leaving the full frame and that’s why we see that that edge we can easily crop that out later okay the other thing that’s interesting is we’ve turned on the auto stretch but nothing seemed to happen in the red Channel but let’s check out the green Channel ooh really bright and the blue Channel looks more normal so in this case the red Channel was really weak compared to the green and the blue that’s reflective of my local light pollution so it’s nothing to be too worried about in any case there is a lot of things that you can do actually right in Cyril with this image processing menu and we can try some of these out it does have a color calibration and a photometric color color calibration let’s just try I’m sure I’m interested what this is so let’s see here image parameters type in m1a1 find pinwheel that’s correct our focal distance was 360 and our pixel size was six point two five microns let’s see what it does okay I took a few minutes I think it’s done it didn’t doesn’t say done in the output log but it did change the image and it does look a lot better actually so that was well worth it um let me actually zoom in woo there we go Wow look at that this really worked yeah don’t like the zoom feature but that looks good it really it really brought out the blue in the galaxy and the star call it looks good too so actually let me explain what that just did what it means by photometric color calibration is it looks for stars in the field where it thereof an own color and then it takes those and it bases the rest of the colors based on those cult stars having an own color and so it’s also a feature in picks insight but I didn’t realize that it was here in Searles so this is really great I’m gonna go ahead and close that and actually I really even just like this Auto stretch looks really good so let’s see if we can figure out how to apply the auto stretch I’m going to go back to linear for a second I’m gonna go up to image processing and down to histogram transformation there’s our histogram and if I just want to apply the auto stretch to the image I can click this button and then click apply I guess seem to work wow that’s really nice so actually this program has turned out to be really really great I surprised I haven’t used it before only thing the the one thing I don’t like about it is that the interfaces are quite clunky I’m having trouble sort of understanding how to zoom and and no no which one should be on top and that kind of thing but other than that this program is really really good I don’t know everything about it yet so just bear with me let’s try this remove green noise next set of a dialog maybe there it is okay this is the recommended option in most cases okay I never and I can’t change the amount okay well let’s just try it yeah like that sure okay let’s see what else is in that image processing menu oh there’s a background extraction option okay let’s check it out okay so it’s it’s very similar to pics insights automatic background extractor let’s try it so that’s where it’s placing the samples can we oh you can also set samples manually left click add samples well right click removes them can I just move a sample oh well let’s just try it with these with this automatic generated samples apply close Wow it’s pretty good there’s still you know there’s still has some gradient stuff down here but that’s really where like you know the frames are overlapping overall that’s quite impressive just want to try to see the galaxies up close and there are you just zooming around and seeing all these background galaxies it’s another one it’s a little bit uh a little bit not saturated enough for my taste but other than that this is really impressive you know I can’t say no how to use some of these other ones so I’m in this stop there with this and we’ll move on to GIMP but really there’s actually not that much we have to do in GIMP at this point because Cyril took care of all the heavy lifting of by removing the gradient and balancing the colors so with a you know really easy automatic processes so this is is it was really nice I didn’t realize how powerful this was it’s sort of like it has some of the the best features of ticks in sight in a free program okay as and for bringing it into Jim I don’t want a fits file I want a tiff file now you might be more familiar with like JPEG or PNG but those reduce the accuracy down to 8 bits and add JPEG is a lossy format as well so you really want TIFF file here for moving it to GIMP and so I’m just gonna call this um 101 0 save it did finish let’s see if I can open it then it’s done yep okay so let me close out of Cyril now quit Cyril or maybe just suck two hits a little red button you sure you want to quit yes okay okay and then let’s open this TIFF file in GIMP and the first thing I’m gonna do is I’m going to crop this to just this central part there’s a lot of weird stuff going on along the edges registration artifacts and strange banding and things that we don’t want and I also feel like the galaxy gets a little bit lost when they when it’s so swamped by this image scale so I’m just gonna open up the crop tool it’s the third row down for over from the left and I’ll zoom in here on GIMP you do shift equals or plus to zoom in and - to zoom out and I’m just going to find a section like that okay I’ll hit return to accept the crop and then I’m just going to go ahead and duplicate this in case I mess up anything so to duplicate you can just right click on the layer over here in the layers panel and choose duplicate layer or you can go up to the layer menu and choose duplicate layer from there I’ll call this duplicated layer curves and I’m just gonna open up the curves command from the colors menu and I’m just going to reset the black point here just by moving this the black point the shadow of the point all the way over here on the zero over and basically what that does is it resets this point as the zero point I’ll hit OK and let’s just try now applying a little bit of an S curve so I’m going to go back to the kerbs command colors curves and I’ll just drop a point down here sort of in the blacks bring that down and then a drop a point up here on the other side of the histogram and bring that up a little bit and you can play around with what looks good to you it looks pretty good hit OK alright I think at this point I might want to duplicate it again and I’m going to call this saturation okay I’m going to zoom in on the galaxy and I’m gonna go back to the colors menu go to hue / - - saturation and just try bringing up the saturation value I’m going to bring it up to I’m gonna max it out to a hundred I think that looks really good you can see the blue arms of the galaxy you can still see the the nice yellowish core that looks really awesome okay I’m gonna click okay let’s zoom back out and see what it did to the whole image it did bring out some of this color noise in the background if that bothers you you can definitely deal with it let’s do this let’s duplicate this layer again just right- click and choose duplicate layer and I’m going to call this mask and what we’re gonna do with this mask layer is we’re gonna zap the color so I’m going to go to colors desaturate mono mixer just hit okay now we have a nice luminance mask here and we want to make the luminance mask a little bit more aggressive so let’s bring up the levels and just do something like something like that so what I’m doing is I’m basically just knocking out the background by bringing the shadow slider way over here but I also brought in the mid-tone slider a little bit to the left to preserve the brightness of the galaxies and the stars okay and then because I want to use this mask to target the background and protect the down the saturation in the background and protect the the galaxies and the stars I’m going to invert it because white selects and black protects so we want the sky to be white and everything else to be black so I’m going to go up here to colors and just click invert it looks like that now and I want to apply this mask to this to a new layer so let’s go ahead and duplicate this saturation layer I’m going to call it D sat BG for desaturate background then I’m going to select this mask just to select all copy it just do copy visible and then I’m going to click on the D set BG layer and right click on it and choose add layer mask and it doesn’t matter yet what I pick here just gonna click Add just do a white layer mask then I’m gonna click on it just left click and I mean a paste so on a Mac that’s command V on windows would be control V it pastes in as a floating selection and we just want to anchor that down into the mask so I’m just going to if this anchor is green anchor button right there and what that did is now the mask is that we’ve created is now the layer mask on this desaturate background layer so let’s go ahead and turn off the visibility of the mask the reason we’re still seeing this is because I clicked it but we can turn it off just like that okay and one thing I’ll point out here in GIMP is when you have the layer selected you’ll see a yellow background yellow dotted line around it and when you have the mass selected you’ll see a green dotted line around it so now with this layer mask applied we want to select the actual image in that layer so we want the yellow dotted line and now let’s desaturate and darken it a bit so I’m going to go back to the colors menu choose hue - saturation and I’m gonna turn down the saturation and turn down the lightness all right this is looking really good I think the best yet we’ll see if pick since I can beat this I’ll hit okay and this is looking good like I said there’s still something that’s bothering me which is this streak right here I think what happened is something went wrong either with the flats like I turned off the camera and the sensor got cleaned or I don’t know what happened but anyways what happened was that there was a dust mote and then the dust mote got streaked because of the drift in the system so I want to fix that just by evening it out with the rest of the background and the way we’re gonna do this is open up our create a new layer from what we’re seeing right here so if we go to new if we go to layer there’s an option the layer menu sorry there’s an option for new from visible so I’ve got a layer menu choose new from visible and it creates a new layer called visible I’m gonna rename that touch up and I’m gonna add a new layer mask to the touch up layer just by right-clicking and choosing add layer mask I want to make it black full transparency is what it says and then I want to paint on this black mask a white brush stroke right there so with the mask selected I’m just gonna grab my brush tool over here in the tool panel I’m gonna bring the hardness of the brush down to zero mine already is but if it isn’t turn it down to zero and then just bring your brush out here onto your workspace and we’re gonna try to make it the right size so that it’s the same width as this aberration so right now it’s a little bit too small so I’m just going to increase the size just Tad’s a little bit more there we go and then I have white selected that’s the foreground color and then I’m just going to draw where I see that aberration just like that if I look at the mass now just by doing option-click or alt-click that’s what I drew in it looks like I look went a little bit overboard over here so let me just try to even that out now with black I just press D to get my black as the foreground color and I’m just gonna even this out a little bit I just look at it again something pretty good I just want to get a little bit of white now down here I’m just going to hit X to switch the foreground and background color and paint that in a little bit okay almost there painting in black a little bit right there okay so now that I’ve painted in that mask let’s now actually click on the image part of this layer so you should see a yellow dotted line down here and let’s go back to the colors menu and go to curves and I’m just going to bring the curves up a little bit more until it’s basically the same color as the background around it now you can see there’s still a little bit left over where I need to paint in the mask a little bit more so I’m going to click back on the mask I’m gonna grab my brush again have white selected again and I’m gonna make it a little bit smaller and just paint in those parts that I missed okay that’s looking really good so I’ve evened out that background let’s zoom back out and see if we can see it nope I think that really did the trick so now I’m just gonna do one final curves so I’m just going to do another layer from visible and I’ll just call this final curves do colors curves and I’m just gonna reset my black point one more time just a little bit and a little bit more and then just do a slight s yeah so that’s pretty subtle let me just bring it down even a little bit okay I like that so this is just about finding the right black level basically so I hit a point right here so that I wouldn’t change this up here and then I just did two little points down here in the shadows and and just lowered those a little bit so just try to get this dark sky level at the right darkness okay I actually think this is our best yet I’m gonna go ahead and save it do you want to return to it in GIMP just do save the normal save command and I guess I will sure I’ll just call it and M101 Siril and GIMP okay and then I do the export to save it as a JPEG I’ll just change the file ending here to jpg to export I’m going to do 100% quality hit export and we can quit out of GIMP now and open up our final results let’s make that full screen and so this is really nice by using Cyril to do the color calibration and stretch and background extraction we got a lot more detail and good color out of this so I think that I am going to probably stop doing my normal thing of doing deep sky stacker plus Photoshop and deep sky stacker plus GIMP and just switch completely to Cyril because it just has some killer features that are very similar to what we get in pics insight that I think everyone will really benefit from so this has been an amazing video for me personally and hopefully you got something out of it too alright till next time this is Nico Carver from nebulaphotos.com and in just a minute here you’ll see all the people that support me on patreon if you want to support me on patreon - the link will be in the description. Thanks so much! Clear skies! .