Generalised Hyperbolic Stretch - Beginner Tutorial

A much requested video subject! - Hopefully this helps someone out there :-)
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timestamps:

[@StevenSchlagel]

Thanks for a concise explanation. It helped me to refine my use of the GHS process and made it much easier to understand and use. Keep up the great work!

[@xyren062]

Thanks Luke. Great tutorial. You've voiced hesitation making these videos before but I'm glad you did. Your tutorial is always fast paced, to the point with practical application and not dwell in the theoretical/technical aspect for hours and hours. Thank you. Keep them coming😊

[@lukomatico]

That means a whole lot to me mate, genuinely. Thank you so much for the lovely comment :-) Hope you have a great weekend!

[@Jcastleinfo]

Great stuff Luke! I've watched many tutorials on GHS and it seems to be the one function where many people have a slightly different process on working with it. I like your style and method. I also appreciate you showing different image types, the RGB, Mono, and Galaxy.

[@lukomatico]

Glad it was helpful mate!! I'm still super new to the process so undoubtedly things will evolve a bit over time, but it's been fun to start using it! :-D Clear skies!

[@josephluciani5531]

Well done Luke! You are a master teacher. All your tutorials make Pixinsight totally digestible. Others offer tutorials, but to be honest, I often wind up scratching my head, discouraged and confused. Not so with your tutorials, you simply break everything down to a level of understanding and application that leaves me not only not scratching my head, but realizing, ‘I can do that!’ Thus is what a great teacher does. Please keep these Lukomatico tutorials coming. And do consider offering a Lukomatico, soup-to-nuts Pixinsight course-I will be first in line to purchase it!

[@lukomatico]

Aw mate you're too kind haha! I do hesitate with tutorials like these sometimes as I'm nowhere near as qualified as others to make them, but comments like these really do make me feel like it's not a wasted pursuit so thank you! :-) Clear skies to you mate!

[@roberthope4723]

Thanks yet again Luke for a very clear and instructive video. Having just downloaded this tool along with RC Astro suite you were the go-to to train myself on these . Keep up the excellent work mate.

[@lukomatico]

That's really great to hear Robert!! I hope you've been enjoying using your new software my friend :-) thank you for your support!

[@deep_space_dave]

Hey Luke! Thanks for creating a simplified explanation of how to use GHS! I think other videos out there go too deep in the weeds with this but your approach is a lot more simple but still very effective. GHS allowed me to take my images to a whole new level so hopefully this video encourage people who previously stayed away from GHS to give it a try as this is a powerful tool! Thanks for the video and clear skies!

[@lukomatico]

Awesome to hear that perspective Dave mate, thank you!! I've still got lots of learning to do still with GHS but there's plenty of time hey! :-D Clear skies mate!

[@maxdobres5193]

Best concise summary of GHS, no nonsense, no waffell

[@lukomatico]

That's really kind of you to say, Max! Thank you for watching my friend 👍👍

[@Wheeljack678]

Wow! This was VERY helpful. Tried GHS briefly a few months back after a recommendation, but couldn't make much sense of it initially. Tried to read a couple of tutorials but they left me more confused so I gave up and instead went back to the tried and true EZ Soft Stretch. I'm gonna go and give GHS another try after I've watched this. I also felt the repeat processing you did with multiple images throughout the video made it even easier to follow. Good job with this.

[@lukomatico]

Hey mate! - I'm so glad to hear you found this one useful, that's really encouraging for me! :-) I appreciate the great feedback!

[@SarahMathsAstro]

You somehow managed to make GHS extremely digestible and easy to understand, Luke! You absolutely killed it with this one (as always if I'm being honest, though). Thanks for all your hard work on this!

[@lukomatico]

That's extremely kind of you Sarah!! Thank you! :-D That means a lot 👍👍 Hope you've got plenty of clear skies over there!

[@trainfan7823]

Absolutely the best explanation I've seen of this tool. Thank you so much! It made so much sense.

[@lukomatico]

You're very welcome! Thank you ever so much for watching! 👍👍

[@paulholdsworth2502]

I've been using it a couple of months now and I personally think it's by far the best way to stretch an image. It's amazing at retaining colour in rgb stars too. Really good video Luke 👍

[@lukomatico]

Awesome to hear it Paul!! :-D I'm very late to the party indeed, around an hour's usage/tinkering before putting out this video lol! I'm sure I'll properly get to grips with it soon though, just need some clear skies on the way! Hope you've had the chance to do some astro now the builders are gone my friend, good luck! :-)

[@OldGirlPhotography]

Just ran across this after struggling with GHS. Thank you so much for this easy to understand and informative video. Really appreciate it.

[@lukomatico]

You're very welcome! Thank you for watching :-)

[@jjjscharf8059]

Luke - Very nice demo/tutorial, I learned a lot. Have to agree experimentation is key as data sets will vary, but you provided some key insights that I appreciate very much. Once again, thanks for your gracious contributions to the community, sharing your knowledge and experience.

[@lukomatico]

My pleasure mate, and genuinely I'm glad it was helpful! :-) Thanks ever so much for the lovely comment!!

[@PRASTRO]

Nice one mate!!! This is my favorite tool on PI, and it’s a really powerful tool 👍🏼👍🏼👍🏼

[@lukomatico]

Thanks so much bud!! :-D Hope you've been well!!

[@arnsteindale5531]

Thanks Luke, just what I needed today 😀 I`ve also became a member of your channel today.

[@lukomatico]

Thank you so much my friend!!! I appreciate your support 👍👍

[@ZeKeeper]

I wish I had this tutorial the first time i use GHS. It greatly simplify the approach of this tool. Great job Luke ! 👍

[@lukomatico]

That's really kind of you to say my friend, thank you so much for that!! :-D

[@iamjessieray]

Another great video Luke! For those out there who don't yet have PI, the latest versions of Siril also have the same tool. I have been using it and it really has completely changed how I process my data. It looks a tiny bit different, but the function is exactly the same.

[@lukomatico]

Awesome to hear that Jessie! - I'll have to take a look at siril again someday, it's a great bit of software! :-)

[@cityspaceastro]

Great Luke yet another process explained well and understood. Thanks

[@lukomatico]

Hugely appreciate it mate, thank you!! 👍👍

[@briankotak403]

Super useful demo Luke! Thanks so much. I just image M16 last night, so I’ll be sure to play with this new tool. Thanks again. Hope you are having a great summer. Dr B from Manitoba, Canada 🇨🇦

[@lukomatico]

Thanks Brian my friend!! It's been a hot but wet summer so far haha, hopefully it dries up a bit soon! Hoping the wildfire situation is calming down for you mate, wishing you the best. Clear skies!

[@Astrobloke]

Top work mate. Nicely explained, thank you and clear skies mate

[@lukomatico]

Lovely of you to say that Glenn, thanks so much bud and clear skies to you too! :-)

[@SimonsAstro]

Nothing like catching up on some Lukomatico videos when I’m out, waiting for the wife, on a wet Sunday 😀 Excellent tutorial Luke, I’ve not tried that yet! It’s on the list mate👍

[@lukomatico]

Ah you're too kind Simon mate, as always :-D GHS is a really super tool, I think you'll like it!!

[@Maximus0389]

Hi Luke! Great explanation. I only recently discovered your channel, but your tutorials have helped me immensely in Pixinsight. Thank you for that and keep it up. Greetings from Germany 😎🤘🏻

[@lukomatico]

That's awesome to hear my friend, thank you ever so much for the really kind feedback! :-D

[@MarkManner]

I've really enjoyed listening to your videos. Just found you, and look forward to more. Best regards, Mark

[@lukomatico]

Thank you so much my friend!! 🙏

[@darkrangersinc]

Excited to check your version of this out. I put out a video on this last week and hoping to learn something new from yours!

[@temayakovlev7850]

I liked your version of working with GHS, thank you

[@jdmatthew]

Watched both of them. Both are well worth watching and got some good info from each. Always interesting to see how a different teacher approaches a topic.

[@darkrangersinc]

I like how Luke did it with the colors I mostly shoot in monochrome these days so I didn’t cover that

[@lukomatico]

Thanks so much for the kind words my friend, that's good of you! - I'm still very much a beginner of GHS, with a total of around 1hr of tinkering before putting this video out lol! I could do with more tutorials myself I guess but my aim was to just get people out there interested, downloading it and having a play you know? :-D Cheers!!

[@lukomatico]

That's a very interesting perspective my friend, thank you for sharing it! - it genuinely makes me feel better about these videos :-) Clear skies!

[@ericwilkes1840]

Great jargon free demo, brilliant work thanks Luke

[@lukomatico]

Many thanks Eric!! 👍👍

[@nikaxstrophotography]

Thanks for this Luke I thought I had it right but that tip about linear black point is a winner

[@lukomatico]

Much appreciate the comment mate, thank you! Glad it was useful :-D

[@Astro_Shed]

Excellent video Luke, you make it look so easy…..👍🏻

[@lukomatico]

Ah you're too kind mate! :-D Thanks ever so much, kind comments are honestly a great motivator! :-)

[@fjrodrick]

Thanks! Excellent step-by-step explanation.

[@lukomatico]

That's so kind of you, thank you ever so much! Clear skies 👍👍

[@mrhornerphysics]

Amazing! Been using the script...finally using the Process ;) Thank you!

[@lukomatico]

Awesome to hear!! :-) Clear skies my friend

[@Tony-Elliott]

Nice tutorial Luke very easily understand thanks for sharing mate

[@lukomatico]

Glad you enjoyed it my friend, cheers!! 👍👍

[@ssrattus]

Thanks Luke, I use Siril and it appears to have a quite similar GHS tool and your tutorial has helped!

[@lukomatico]

That's awesome mate! I'll have to take a look at it some time :-D Siril is a great tool!

[@davidpayne8646]

Nice job Luke. Much better explanation than I can give!

[@lukomatico]

Crikey mate that's seriously high praise!! - Thank you so much for this incredible tool and for all you do for the astro world! :-D Clearest of skies to you my friend!

[@davidpayne8646]

@@lukomatico Same to you - thanks for all you do!

[@petesastrophotography]

Nice tutorial Luke. I really like the GHS tool and have used it for a while now and prefer it over the standard histogram tool👍

[@lukomatico]

Thanks ever so much Pete! :-) Glad you liked it mate, I'll be honest I've got a lot of learning to do still myself with the tool but it's all good - hopefully it encourages people to just get it downloaded and have a go you know? :-D Clear skies my friend!

[@petesastrophotography]

@@lukomatico Yes indeed, the more people that know about it the better. GHS isn't always the best option in every situation, but the great thing about the tool is that it lets you also do the arcsinh and regular histogram transformation in single tool while still being able to specify the symmetry point to target where the stretch happens🙂Also, just wanted to let you know that I have uploaded a couple of processing videos to my channel using the data you have shared. I have credited you in the description with a link to your channel but I wasn't sure if that was working or not (still a noob on this youtube malarkey!).

[@Si-fp2ij]

Very good tutorial Luke 👏🏻👍🏻 Cheers Si

[@lukomatico]

Thank you! Cheers! 👍👍

[@didiermicoud8227]

Thanks!

[@lukomatico]

Thank you ever so much for that mate!! :-D That's really kind!

[@mr.d.8121]

Thank you 🫡

[@lukomatico]

Thanks so much mate!!

[@dumpydalekobservatory]

Nice one mate as you know I don't have Pi but they do have GHS in SIRIL to, I've never used it myself I think it's probably about time I did.

[@lukomatico]

Absolutely mate!! Nothing to lose, give it a go :-D

[@duke227]

nice skills!

[@lukomatico]

Thank you! Cheers!

[@joakimastro]

Guy did it!

[@lukomatico]

Haha! you pushed me over the edge my friend :-D Clear skies!

[@janelubenskyi1177]

Thank you Luke….during this stretching in GHS how do we attend to the saturation of color ….would you please make more videos on this subject.

[@lukomatico]

Hey there! :-) To be honest, so far I've just been doing my saturation adjustments still with masking and curves, but as soon as I know more about how to use GHS for this I'll make a video from it, cheers! :-D

[@alfredterrence6112]

Finally, I understand how to use this module. Do we apply GHS to our images after or before NoiseXterminator ? Thanks so much !

[@mr.d.8121]

Hello. I believe a good process goes : DBE - SPCC - BXT - NXT - GHS/HT ( or EZ 'soft strech)

[@lukomatico]

Hey Alfred! The workflow suggested by Mr.D is a good option, I myself sometimes apply NXT again later in processing too :-) Sorry about the late reply!

[@SKYST0RY]

Do you still use this thing? I just can see no point in using GHS instead of the Histogram and Curve tools.

[@lukomatico]

I do indeed still use it my friend! I find it works well, I agree that a careful stretch without this tool can still look absolutely fantastic though! 👍👍

[@dlmackie123]

Will you use this when you are going to use Bills HOO (or SHO) Normalisation - he recommends to use unlinked stretch. I tried GHS before HOO Normalisation before and did not have great success. Like your channel very much BTW.

[@lukomatico]

Thank you mate! I'll get around to giving it a go I'm sure, there's always something new haha - it's hard to keep up! 👍👍 Clear skies!

[@kowalskik.1333]

Hello Luke, I am confused because I was teached to remove the stars before stretching to avoid blowing them up. Dont you do this? Why not? Thanks a lot

[@lukomatico]

Hey mate! - It could be useful to do that in some situations yeah! I guess it's all down to your aims for the particular data set you're dealing with :-) I often like to remove stars in the non-linear phase of processing these days just personally speaking! The best course of action is experimentation! :-) Good luck to you my friend and clear skies!

[@kowalskik.1333]

@@lukomatico :D Good diplomatic answer ;-)

[@carvrodrigo]

Hey Luke, thanks for the video. I’m moving from Siril to PI. I saw your series about PI and you use EZ SOFT stretch. Right now did you move from Ez to tailor made GHS ou just using it for specific cases? Thanks again!

[@lukomatico]

Hey there my friend! - I do tend to use GHS more these days, I've mostly stopped using EZ tools now :-) I still think they are good, but there's definitely better options available! Cheers!

[@carvrodrigo]

@@lukomatico that was my bet! GHS in Siril is very powerful! Keep your hard work man, your channel is on point! Congratz!

[@SKYST0RY]

Do you have an Astrobin channel, Luke?

[@lukomatico]

Hi mate! I do have one under 'Luke Newbould' - but it's extremely infrequently updated and not very populated as I don't have AB premium!

[@billashman1717]

Great video. 1 question how are you zooming in on the Real Time Preview Window?

[@lukomatico]

Hey mate! - you click the topmost tool icon in the preview window, this allows you to drag a selection box which becomes your new zoomed preview :-) hope that helps!

[@billashman1717]

@@lukomatico Thanks for that. It doesn't appear to work for me. When I click the top icon (circle) I get crosshairs then, when I left click to select a box I just get the image RGB information box.

[@sethjchandler]

I appreciate this video very much, but I think there is a pedagogic problem, which is that you don’t explain really why you are doing what you are doing. that is, what is the problem that you were trying to solve with each of the operations you undertake. and without an understanding of why, it is challenging to generalize your approach to other images that we might work on. For example, can you describe in English what moving the symmetry point is designed to accomplish?

[@lukomatico]

Hi there my friend! That's very fair feedback, thank you so much for taking the time to offer it! :-) I tend to keep longer explanations for the purely 'tutorial' based videos rather than new release/awareness videos like this in order to keep the video length down 👍 Regarding the symmetry point, - the position of this point is the position on the histogram through which the curve line will try to keep as the middle of it's 'S' curve, having the symmetry point set wrong, e.g too far forwards or backwards in relation to your histogram distribution will place the S curve less accurately through the data, - that's about it as far as I understand it! 👍 Hope that helps and thanks again for the feedback - Clear skies!

[@sethjchandler]

I appreciate your feedback on my feedback. I know that making videos is a ton of work and you do an excellent job.@@lukomatico