Very nice video. Very pleased to find someone using command line ;). Cyril Richard - one of the dev of Siril.

@BorealisLite

3 жыл бұрын

I am honored sir. The more I learn the more I find to like and respect about your amazing creation. There are 2 other vids in this series devoted to Siril. My thanks!

very good video.

Thanks again for sharing your learnings with the community. All the best Gary!

Very nice. thanks Gary

Hi Gary :) Once again, I find your videos very helpful. I have few questions. 1. When you are doing Asinh Stretch in Siril, is it color preserving? In your other videos you said and demonstrate Asinh Stretch in Gimp but to actually preserve the colours you had to create additional layers as it is referenced in the original paper for this technique. Siril does it automatically under the hood? I know that Siril does not have "layers" at least available for user, so that is why I'm asking 2. How do you know when to stop doing Asinh in Siril, and how you assess the proper value of black point to set? 3. I have noticed that you are doing Histogram stretch after Asinh stretch in Siril, why? And how do you know when to switch? 4. Do you think that applying background neutralization two or more times on an image in Siril makes sense? I did it on one of my images. 5. Does applying both, color and photometric Color calibrations is not in fact overriding the results of the previous one?

@BorealisLite

3 жыл бұрын

Hi Kristoff, a worthy set of questions, will try to take them in turn. 1: I agree, Siril does not have layers and I don't know if it does that in the background or not. I do know the original ArcSinH stretching article referred to stretching the greyscale multiply layer of a multi layer set, but most seem to just apply the stretch directly to the image with success. I also know that Siril is sophisticated and believe their implementation of the method to be effective. I first started stretching in Siril because the results were better than I was getting in GIMP. 2 & 3: In these videos I am primarily trying to make you familiar with the available tools. In my case I have deep chromatic aberrations in many images so I lean more on histogram stretching to make that less apparent. On the better ones I lean more towards ArcSin stretching for the color preserving aspect. In my experience with Siril I have found that if I do ArcSin stretching in the arcsin preview mode I can do the deepest part of the stretch that way. But upon switching to linear view, it is still not fully stretched. At that point I used histogram stretching to finish for the simple reason that it gives you a histogram with which to better judge black point etc. The ArcSin window has a black point setting, but no histogram so I try to choose a black point that is not completely black to avoid clipping. 4: Interesting idea, will give it a go! 5: Again I was demonstrating various ways of doing things. I like to do a manual calibration and follow up with a photometric one to compare, and ultimately use the one I like better by doing an "Undo," or not. I am about to level up in equipment to ZWO with guiding etc, so I am planning to use Siril for everything up to "ready to stretch." Starting to investigate free tools with an ArcSinH function, but also with a histogram for a finer degree of control.

@toolan

3 жыл бұрын

​@@BorealisLite Thank you for response ;) Add 4. I did it in below workflow: background extraction -> color Calibration -> background extraction. After the second background extraction my image was significantly better but maybe its something specific to may camera and location where I'm taking the pictures. I'm asking those maybe to much detailed questions because I'm just learning this stuff and I would like to avoid "silly" things that I might do. For example applying two operations that would cancel each other out :) That is why I really appreciate moments when you go slightly deeper and actually explain what concrete operation does, like for example the Screen mode.

Gary, You mentioned - in video 4 or 5 - about doing a gentle background extraction on preprocessed but not stacked lights. I'm looking in the Process folder and can see a pp_light_seq file, plus the pp_light_.fit files and everything else....how do I do this ? Am I having to select each individual pp_light_ fit file or just the seq file and it syncs it to the fit files ? Rather confused, I can see the potential benefit but it wasn't something you spent any time explaining....I don't think. Thanks for all your hard work !

@BorealisLite

3 жыл бұрын

Hi D J, thanks for writing. I wrote a script for that that resides with my other scripts on google drive, linked from the comments in those prior videos. It is easy to do manually too. If you have the pp_light files, you are good to go. Just switch into the process folder in Siril (command line type cd process) Then in the command line type seqsubsky pp_light 1 That will run the background extraction on each light in the sequence, and generate a new sequence called bkg_pp_light. Go to the sequence tab, search sequences, load the new sequence. Got to the registration tab & hit "go register" Then there will be a new sequence called r_bkg_pp_light that can be loaded in the sequence tab, and stacked in the stacking tab subject to your filtering wishes etc. When done just be sure to take siril back to the main folder by typing cd .. This is so it does not get hung in the process folder. Hope this helps, if you can get the script its easier. There is a readme.txt file with the scripts that should be helpful. Cheers.

@curlingdan

3 жыл бұрын

@@BorealisLite Thanks Gary, I do have the scripts and am going to try it on some older frames I took back in November. I'll let you know what happens....I'm slow but I'm still learning !

Hi :) Which version of NIK Collection Tools you are using and what "extension" you putted as a last parameter in ShellOut.py lines in programlist array.

@BorealisLite

3 жыл бұрын

They are part of the pre dxo package, version 1.2.11 from www.techspot.com/downloads/6809-google-nik-collection.html If you are working with 16 bit images only you can pass a tif. If using 32 bit images it pretty much has to be a png but conversion takes longer.

@toolan

3 жыл бұрын

​@@BorealisLite Ha, interesting. I installed this one nikcollection.dxo.com/ which seems to be the same thing but version, not a Google and paid ;) However there is 30 days tray period. Other than that is seems to be the same thing that you have. Your one is free right? I'm asking about the file format because even I have a "png" defined in shellOut.py script for DFine 2, NIK prompts me with some kind of warning about using Jpeg even though I have TIF opened in Gimp.

@BorealisLite

3 жыл бұрын

@@toolan if you are using 16 bit images maybe try "tif" That is not about the open image, it's about what gets passed to nik. If you use jpg it is completely lossy and will degrade the image. The version I use is pre dxo, so it's the google version as it existed then, and is free.

@toolan

3 жыл бұрын

@@BorealisLite Yeah, currently I'm working on 32bit file and the thing is that I do not have anywhere in shellOut script "jpg" thats why Im surprised. I will try to sort this out, thx.

Tough to follow along when the key strokes are so quick. Slowing down, just a bit, would be helpful.