Intermediate Siril: Pixelmath
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- Опубліковано 2 сер 2024
- This video is devoted to introducing pixelmath in Siril. This is a powerful tool that might me familiar to people who have used a certain high end astro processing program. It might be less familiar to devoted Siril users like me.
In this video I introduce the interface and use it to demonstrate a few different use cases, the best way to learn. This is not meant to be exhaustive, the possibilities are infinite.
I am away from home now, limited to the microphone built into my laptop, pls forgive the audio - not to mention a tendency to ramble a bit from working 18 hrs yesterday. :)
Table of Contents:
0:00 Introduction: The interface & basic concepts
3:19 Preparing the images - Stretch, align, channels
14:50 Use case 1, synthetic channels from existing channels
19:27 Use case 2, synthetic channel using inverted pixels
28:44 Preparing the images for Ha integration
32:26 Use case 3, adding Ha data to broadband images, linear
44:11 Use case 4, adding Ha data to broadband images, stretched - Навчання та стиль
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Super cool! Complex topic is very well explained .
Thank you!
Great video, thank you. Not only am I new to using Siril but I am new to astrophotography. Your tutorials on Siril are really helpful showing the power it has and seeing techniques used in processing an image. It is much more than stacking software!
Thanks Jonathan, I agree completely. And being open source many can contribute. There are reputedly works in progress that should propel it into a leadership position.
Most excellent content and delivery, looking forward to your future tutorials on siril.
another good tutorial Gary. Although I still really dont understand all the formulas and such. I'm sure I will watch it a few times
Awesome Tutorial so much to learn!
Thanks Nik, I really need to redo this with a better mic... but I felt it important to get something out on pixelmath. Cheers
A very thorough presentation of Pixelmath. I will probably add a Siril tutorial (or a few) to my channel too as I am an avid Siril user too. Your tutorial is very clear and an inspriration!
Thank you Martin, I had issues expressing myself in this one, may redo it. But glad it helped. I thought the best way to see how it works was to just dive in. It opens the door for us to many other tutorials about PM that are not Siril based. Cheers
Great tutorial…please do more pixel math in the future😊🙏
Thanks Jane. The possibilities are infinite. I'll certainly add as I find more applications that work for me. Pixelmath may propel me into mono imaging where it can really shine.
Can't wait to see what you make of the recent upgrade changes to Siril.
Thanks, I've had a winter of clouds & want new data to work. This week looks good! Deep Space Astro has done some great work on the major changes, I think I'll focus on the multitude of smaller ones. There is very cool stuff in there if you dig a bit. Regards
@@BorealisLite While you're waiting for the sky to clear would you be good enough to have a look at StarTools. I've only played around with the free version but I can't get on with it. I know others rave about it but your thoughts would be gratefully recieved.
I for one am eagerly waiting for the photometry/astrometry video you mentioned. Would really be interested to see how it compares to the measurements you’d get from AAVSO software which doesn’t go any of the preprocessing. If Siril can be a one stop shop for everything from the calibration to registration to measurements to light curves - that would be AMAZING!!!
@@eacron Hi Ron, I'm planning to make a new vid on Saturday. Siril needs a plug in for light curves. I've not done that but will get into how to set up for it.
Regards!
Great!! Looking forward!!
thanks
Great video! Will you do a similar video on doing photometry in Siril? Thx!
Forget StarTools I'm Siril all the way!
Thanks for the very helpful video! Can You explain how to add a luma channel using pixel math?
Good question. In all my research people use the rgb combination tool for rgb combinations with luminance. If you are trying to use a synthetic luminance from sho data it can be generated with a pixelmath expression like
(Ha^2 + Oiii^2 + Sii^2)/(Ha + Oiii + Sii)
To use it I would assume you would have to split channels & use it as lum in the rgb combination tool, or as a layer in PS or GIMP set to luminance blending mode.
So far I'm only using pixelmath for narrowband data, I have not seen much of anything on it for lrgb. Sorry I can't help more...
Hi
Maybe a silly question but I to have the asi533mc And Also use the L eXtreme filter, when you say open up the ha and o3 subs at the beginning I may have missed how you achieved this ? Could you explain please?
Hi Ross, not silly at all. I had run the extractHa&Oiii script in Siril to produce those files. It's an inbuilt script that produces a mono Ha_result.fit file & a mono Oiii_result.fit file from duo narrowband captures. I did it this way to produce channels that need alignment, something I have been asked about in the past. A different workflow would be to split the channels from a normally processed L-extreme image. If you look up Craig Calvert on UA-cam he does this in his synthetic SHO workflow.
Hope this helps!
@@BorealisLite many thanks
When converting images to a sequence to then be used in Pixel Math.....how do you keep track of the R, G, B, and Ha files after you convert to sequence and/or register, so that you can name them properly in Pixel Math to make the equations work? The names get generalized to (0001, 0002.....), and other than eyeballing the individual sequence FITS against a screen capture to try and match original file to sequence file, I can't keep track of all 4 channels (RGB and Ha). I'm sure I'm missing something easy or fundamental......
If you actually shoot lrgb with a filter wheel most capture software will tag the subs with the filter & Siril will preserve this through stacking. In this case the stacked channels will already be named in pixelmath with the filter name. In this video I split channels from an OSC image so no such data exists. But I simply registered the Ha to the red channel, (if memory serves,) so there is only r_align_ 0001 & 0002. 1 would be the red reference channel & 2 would be the aligned Ha. When opened in pixelmath I just immediately give the Ha a shortcut name so as to not forget, lol, then bring in the R,G,B from the split osc image.
Hope this helps, in more complex scenarios I actually rename the r_align_0001 etc with windows file explorer prior to loading pixelmath.
Right - I’m doing same - Split broadband OSC to RGB and then same for Lextreme over OSC, and take red channel from LXtreme as Ha. So, Siril will name 0001 to the first one loaded in the conversion/registration, and so forth? I just had no way to verify and couldn’t find an answer online.
@@rkdodds Every time I've aligned Ha to red I've loaded the red first into the conversion window, then the Ha (or whatever name you give it when splitting the Red from the L_extreme stack,) second. Then make the Red into the reference frame, then after registration 0001 will be a copy of the R, 0002 will be an aligned version of the Ha. Seems to work reliably that way, but I still check visually to be certain. It's a bit cumbersome but registration works much better than the alignment tool available in the lrgb tool.