Completely manual image processing in Siril 

This is very dated now, but I'm pleased if it still helps. Siril is way more awesome now but the building blocks remain valid. Cheers

@@BorealisLite I've seen some features that caught my interest that have improved since this version, pairing the current documentation with this video helped a ton because my main issue was actually being able to visualize a workflow, so I'm really thankful I found your tutorial, thank you for sharing your knowledge ☺

Thank you Paul, really glad that this helped !

Paul said everything I had planned on saying, so let me acknowledge him and acknowledge you, Gary. : )

Thank you for your kind words. Everything I have learned comes from other members in the community, and that led to the ability to recognize the power of the effectiveness of certain knowledge. That is what this channel was about, and will continue to be. It is my attempt to bring something back to the community, and I look forward to the day when you and others who started here can do the same. Cheers

Thank you, appreciated !

Thanks! I think it is a good thing to understand what is happening under the hood, especially if you will be creating/modifying scripts. Regards

Thanks Michael, that has only happened twice and I was running screen recording both times. Hopefully that is what caused it. Regards

Hope it helps, appreciate your comment.

Thanks Jon, my 135 & 200mm primes are also from the late 70's. In some ways they are perfect for astro. But I attribute the quality of my images to Siril's linear processing steps.

Hi Gary. I agree totally,I’ve seen a big difference in my results from using SiriL and following your process.I’ve heard using a Skylight filter with old lenses may help against the chromatic aberration they suffer. I’ve now got one on order to try out on my Chinon 200mm screw fit.

@@jonbasstro1413 That sounds very interesting... pls share any insights with us at the time. Would like to hear of this!

@@BorealisLite I will keep you updated on how it goes with the skylight filter.Intention is to shoot a nebula for 60-90 mins with and without the filter on the same night.Will try and link above/below where I came across it.

Thanks for this, I have also found darkTable (free alternative to Lightroom) has some ability to isolate & desaturate CA. It is on my list to do a RU-vid about. Regards

Thanks for sharing your results. I looked up the filter, apparently it subdues blues (warming). So maybe helps with the blue CA, at the cost of letting in less light. Would be interested to hear your comment after a dark night test. Best of luck!

@@BorealisLite Hi Gary, I think that sounds about right on what you commented on.Will keep you updated. Regards.

Hi Gary, I did the star check with and without the skylight filter under a moonless sky with a 200mm lens. Unfortunately I could see no improvement in the image. However,I have discovered another method in my search that would hopefully improve my star and ultimately DSO images,this is using “step down rings.” My 62mm aperture 200mm lens using the step down rings has been operating at 49mm and even 37mm aperture,in doing this the camera lens can operate on its F stop fully open,the stars have been virtually pinpoint with little to no CA.This has improved my imaging results over the last few nights and the loss of aperture does not appear to effect the final outcome.Worth a try. Cuiv The Lazy Geek explains it in the following. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-D78P1h_a50Q.html

@@jonbasstro1413 Thanks for this idea! Sounds very good, even if it may mean more subs. That would take less time than trying to effectively process the CA. My regards, going to try this next chance!

@@BorealisLite Look forward to hearing back how that goes for you.I’ll be using the step down rings on my old lenses from now on.All the best.

Hi Chris, I do realize the learning curve is huge with all of this. It comes in steps, eventually becomes manageable. Some people do shoot targets over multiple nights to get enhanced data. One strategy is to use the same settings and to just get more subs. For high dynamic range subjects like Orion many shoot longer exposures for the nebulosity & dust but also short ones for a core that is not blown out. Then a blend using aspects from each. With a cooled astro cam on a scope we can re-use dark frames of the same exposure length & gain. But we need new flats and flat darks. With a dslr on a prime lens the opposite is kind of true. Darks are unique to the sensor temp while shooting, but so long as there are no new dust spots on the lens, the flats and biases can be used across sessions. Truthfully, in the winter when it is cold, I never used darks with my dslr. Instead I would just use biases to calibrate the lights. So my biases would go into both the "darks" and "biases" folder in Siril. To address your question, the images from each session need to have close to the same framing for stacking reasons, and if you do use calibration frames then each session should have its own as required. At that point they can be preprocessed with their calibration frames, then gathered until done, and finally registered and stacked as a group. In this way images with different ISO or exposure times can be stacked together if appropriate. In all truth, until Siril becomes second nature I would use the groups feature of Deep Sky Stacker to keep it simpler. You can place the images from each session in a DSS group with its calibration files, and it will align & combine the sessions properly. At that point the output file can be opened in Siril for operations like background extraction, color calibration, & stretching prior to export for further work. If you have a short exposure set for the core of Orion, it can be put in a group with none of the images selected while you are stacking the longer exposures, then all of them selected but none of the others for stacking the short exposure group. You would use the original reference frame to get matched alignment. The nebula will be well illuminated without shooting over multiple nights, if you are going for a wide field with Barnard's loop etc, then more time may be justified. I hope this is helpful. There are a lot of RU-vid vids about each aspect of this I have mentioned. I think the key is to take on one thing at a time until it all makes sense. And keep every raw sub, you may want to go back and reprocess or add in the future. 🙂

Thank you so much for your reply .keep up the great tutorials really appreciated

Thanks Johnny. Version 1.2 is pretty big, it has a lot of new & improved features to learn. I'm still trying to work out an optimal workflow for most of them...

@BorealisLite I am learning too, but I am a newbie of Siril. Look forward to your great tutorial ! 🙂

Thanks, I was asked to do this so some could better understand what happens under the hood, so to speak.

Right beside the "Start pre-processing" button there is a debayer before saving check box. That is the most likely thing.

Thanks! I have not yet done mono, just upgraded to a ZWO OSC cam. I do believe that Siril is capable though. You could run each set to a stacked final, and then try RGB Compositing from the image processing dropdown. There is an alignment tool in there, and room for a luminance channel. From the command line there is also a command called linearalign. It takes the open image and aligns it to the reference image that you enter as a parameter. I have never tried either from my dslr history, but if you recognize these tools you may be ready to use them. Siril also has a function to split Ha and O3 from a dual filtered set, if I ever get some clear sky witn no moon I am planning to shoot a galaxy with the l-pro and with the l- extreme and try to mix the Ha channel from the Extreme with the RGB from the l-pro. But not there yet! Best of luck.

@@BorealisLite Yes it is. I will get that figured out once I fully understand these scripts. Looks like you should be able to build your own script for any custom configuration you want.

@@TheNarrowbandChannel Indeed. When you run your mono images you could use the same darks & dark flats (bias) for each channel. Just need unique lights & flats for each filter. If you look in a text editor at the script files you can see how they work. I would just have a flatR folder, a flatG, a flatB, and a flatL folder for the flats. Then you could open/Save AS the full processing script and just change the folder references in the flat section of the script, remove the debayer & osc commands in the preprocessing section, and change the ouput file name in the stacking command for each new script you create.

Hi, one of my vids earlier talked about calibration frames in more depth, but in short 25 to 30 will do 80% + of what thousands can do. I would never go beyond 40, there are diminishing returns. 🙄

@@BorealisLite thank Gary…you are so kind to make such a speedy rep,y. 😊

Hi Jose, very dark frames are normal depending on the capture. They are linear, or as shot. We calibrate, stack, & do some processing in the linear state. Siril has a button in the lower center where you can choose a view. If you choose autostretch it will show you a stretched version of any image without actually stretching it. This is powerful because you can see what you are doing while remaining linear. It is covered in some of my earlier vids in this playlist. It is my hope that is what you need. Regards

Thanks Gary, this sets of lights that I am processing were processed with pix insight with no problems by myself, the Siril testing error is when y try to preprocess the lights applying the darks and flats, I am following your steps one by one and everything is ok until I preprocess the lights, somebody told me they is because I am subtracting twice the bios, I don’t know how if I am following your preprocessing steps one by one, your videos are excellent, but I can’t continue thank you so much for your time, I wonder if I can send some screen prints with my results, if it’s possible

@@jfn480427 Thanks for getting back to me. I can't explain it, but if you have pix & it's working for you then I think you are good to go. I am curious but the only way to send big files is by link sharing from Google drive or similar. If you want to do that pls feel free but not obligated. Regards!

Hi, you could certainly try that, but for best integration I would actually try calibrating all your sets into a large group of preprocessed lights & register them all at once. If that succeeds, then stack. If not there is the option to stack each set and to try to stack the stacks. If this fails maybe put a few subs from each set on google drive & I can make a short video about it...

@@BorealisLite thank you Gary for your speedy reply 😊

Siril works on seq …and how would I be able to get more than one seq at a time to be registered together….to my understanding it can only register one seq at a time…is there a way…please tell me how😊

@@astronomynotebook Hi, I assume at this point that you have preprocessed & debayered all your lights with appropriate calibration frames, and that you have several sequences like pp1_light.fit, pp2_light.fit etc. in the process folder. At this point you could delete or move all other files from the lights folder, and from the process folder. Then drag all the preprocessed lights into the lights folder, add all them all to the conversion list in the conversion tab, and convert them. They don't need conversion, but this will create a new sequence with them all in it. From there go straight to registration. If Siril can find common alignment stars, they should all get registered, ready for stacking... Because of the differing image scales there will be significant stacking artifacts to crop out, but all shared areas should be there. Hope this helps!

@@BorealisLite yes it does and you are very kind to have helped…please consider joining my Astronomy Notebook FB Group facebook.com/groups/350767592003671/

Hi Jack, mine is for the few hot days we get, I just set it to about 27C and it dehumidifies to a tolerable level. If you need heavier use, I would get something that does its hot air exchange outside, this one blows interior air outside all the time it's running & creates a vacuum that draws humid air in everywhere else. That is less than ideally efficient. Cheers

@@BorealisLite Gary, thanks for this. I did not understand how these units worked. Pulling air in from the outside is NOT what we want. Last September we went through a week-long period when we could not open windows because of wildfire smoke (western Oregon). It was terrible. I decided to create a safe room that had a/c with no outside air exchange and a hepa air filtration system. The ductless mini-split satisfies the a/c part of the system but I was looking for an easier/cheaper solution. Thanks very much for you input. Clear skies.

Hi Greg, your idea is completely valid. I started using Siril by opening tif files from dss & going from there. I think dss can also generate fit file format stacked images too. Also, this is the manual process. Siril is much easier when using scripts as described in my earlier vids. This one came about from requests from some who wanted to look deeper. Cheers

@@BorealisLite Great. I'll try it. Thanks so much.

Sure, will look at that tomorrow. Cheers

Hi, that's very little information to go on but the first thing that comes to mind is that a dslr will switch to portrait mode from landscape or vice versa as a cam rotates, unless that is turned off in cam settings. Also when you convert from cam raw to fits the dimensions can change a bit. They all should have the same conversion applied. I have to go to work for 14 hrs now, can respond further after that if needed. 😊

@@BorealisLite I went through the online manual for my camera, and the difference, is because of the difference between the selected aspect ratio 3:2 instead of 16:9 or vice versa.

@@MRCAGR1 That would do it. On my Nikon I don't recall even having that setting when shooting raw, but hopefully that will allow you to move forward now. Regards