GHS Part 1 Getting the Most out of Your Data!
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- Опубліковано 29 чер 2023
- Time stamps:
3:35 - Start of Tutorial
12:50 - Bat Nebula
20:45 - 3 GHS images
HOO pixel math used in the video:
R = (Oiii^~Oiii)*Sii + ~(Oiii^~Oiii)*Ha
G = ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Oiii
B = Oiii
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Concise, easy to understand and to-the-point! Thank you for this video. I have been struggling as a new PI user and this really helped with GHS. Your channel is an asset for the community.
Best explanation yet
Thanks for the feedback! I have some more GHS stretches in my late 2023/2024 processing videos that I think is even better. Just had to get better myself and better at explaining. We’re all learning.
Definitely worth every second watching - showing workflow while explaining GHS is gold!!
Thank you so much, if you watch my 2024 Pixinsight overview. I also go through GHS pretty thoroughly and explain it in a way that was helpful to some of the folks. I coach one on one so if you need any further help that should get you squared away.
This was amazingly enlightening. this example was by far the best explanation ive seen
Out of all the GHS tutorial videos out there, this is by far the best one I have seen. Keep up the good work Ryan!!!
Best GHS tutorial I’ve found! You’ve clarified a few things for me and showed me a slightly different way to use the local intensity feature. Thank you!
Glad to hear I have a second version out too that I did after a few more months using the tool
Excellent tutorial, thank you and clear skies!
Thank you sir! Let me know if you have anything else you want covered.
I’m planning on doing a video comparing a few different HaRGB combination methods soon.
Ok
Right off the bat
Props for the point out of the actual tutorial start time.
Point blank, hands down The best explanation and tutorial on GHS on UA-cam.
I've listened to hours of bloviating on this subject by the 'experts' and came away with nothing.
No selling your product, No self puffery, just a complete 20 minute Masterclass to help your fellow astrophotographers.
Great job Ryan
What else you got...
Thank you! You make a good point. It’s actually harder to be short with videos than it is to be long. In this case, since Adam already had a video out going into the weeds pretty deep, I figured if people wanted more background, they could go there and I could just show them how to use it.
I did post a follow up to this on Monday with my process after Pixinsite in Photoshop if you use that
And tomorrow I’m releasing a start to finish full tutorial on the ASIAIR. You probably would obviously not need that but if you have any friends that are beginners, it could be helpful.
Topics requests are always welcome!
Thanks! Amazing Tutorial, helped me a lot :)
That’s awesome glad to hear thats my motivation for making these. If there’s anything else you’d like to see you, let me know.
Spot on Ryan! Thanks for taking the mystery out of GHS.
Thank you for the kind words glad it helped. Let me know if there’s anything else you need
Great video Ryan - a really clear explanation of how to use GHS.
Thanks for all the work you put into it. This and your newest Normalization tools are the biggest game changers of the year!
Great tutorial 👏🏻
Awesome job and thank you for sharing !
Thank you glad it helped!
You are great asset to the community. And a classy dude. Thanks for doing this. I will be watching this about 400 times.
Thanks, Joe D
Haha thanks! I cover 2 target so hopefully only have to watch it 200 times! You’ll see how much easier it is on the bat nebula because it’s not nearly as faint
UA-cam suggested your channel during my GHS tutorial search, glad it did! :) I'm gonna go thru all your videos very soon! ;)
Glad to hear! I’m actually going to release a video tomorrow that will have unlinked stretch and finishing it with GHS going through the different RGB color stretches
Great demo. You 100% got it and explained it!
Thank you I appreciate it! I just released a video yesterday and there are two newest scripts if you haven’t seen it
Nicely done, provided some insight that other videos lacked, and likewise found part 2 very informative...
Good to hear! Most YT videos loose half the audience by then but for those that stick around sometimes it’s worth it 😃
This is a very coherent and sensible tutorial on GHS. I have seen others that make a lot of what seem to me arbitrary changes to the local intensity that I don't understand and that have not resulted in particularly appealing results when I have tried it myself. Your approach seems more approachable to non-specialists like myself and has so far resulted in very appealing outcomes on my data. Thank you so much!
Great work, excellent! As a newbie, you made it very clear .
Awesome to hear. If you use Photoshop or are thinking about it, I just released a video on Monday for what I do after Pixinsite.
Great tutorial !! I've been using the tool now for about a month but I've learnt much more from your tutorial. Thanks so much for posting this
I have really appreciate that and I’m glad you found value in it… if there’s any thing else you’d like covered I’m always looking for a video ideas!
Best GHS tutorial I’ve seen. Thanks.
Appreciate that Pat thank you! I came out with a second version that shows a different way to use the symmetry point slider in addition to flattening out the high points in the histogram. as well as a shortcut to get through the first few steps and get to the point where GHS can go above and beyond an auto stretch.
@@darkrangersincI cannot find it. Could you please provide a link?
@@patthompson9973 it’s a little more recent it’s has a picture of the blue horse head nebula on the thumbnail
Nice. Still trying to learn GHS and now I’m inspired to keep trying
I’ll have a video working with a new person to the hobby coming out Friday and we used GHS so stay tuned he’s actually controlling the mouse making it a little bit easier to follow along!
amazing tool, thanks for sharing!
Absolutely thanks for watching!
finally a clear explanation how GHS works! thanks a lot, for this video and congratulation s for Bat Nebula result, very nice work
Ciao and clear skies
Roberto
P.S. I just signed up 😜
Glad to have you as a part of the community and thank you! The most recent processing video I put out a week or two ago, goes into pretty good depth on GHS again, and shows a little bit different way to look at it neither is really right or wrong, but someways work better for other people
I captured 4hrs of M45 a few days ago. I had to discard half of it due to clouds that i didn't see visually on the night of imaging because they were high up and very thin, however, they were obvious when i used Blink. I was able to get an amazing image using GHS out of the remaining 2hrs of data after watching Adam Blocks and this tutorial. Thank you.
Great video, really helpful
Glad to hear I appreciate it.
You are an outstanding educator and I am really glad you are here. The more styles, approaches and use cases the better. You really brought out what GHS is doing and why it is so much better than the other stretching techniques. I came here today as I was struggling with the 'shelves' in my curves processing my data I captured last night and you really nailed it. Shelves are areas where data with different levels have been squashed into one thus losing data. Welcome and thank you.
Thank you Ian that’s really kind of you to say I appreciate that feedback and I’m glad that you were able to take your image to the next level 💪🏼 🙏🏼
Thanks for the GHS tutorial. I tried the process a few months back. Some targets worked for me and others didn't. You explained WHY you did each step.
That’s so good to hear! It’s tough because I don’t want to make the video is too long so people actually watch, but I also want to make them through enough to make them useful!
I’m not familiar with GHS so I’ve been watching a few videos to get an idea of how to use it. So far, hands down, this has been the most useful video on the subject for me.
I’m glad to hear that it helped. It’s a great tool and I think you can help everybody take their images to the next level!
That is amazing! Thanks for sharing!
Thank you so much glad it helped!
Good job buddy!
I watched Adam’s video and then yours. I don’t have all the tools in Siril that PI has, but wow this tool is amazing. Hoping this stuff sinks in! 😂
Great video! Thank you. I've used GHS in Siril before and been happy with it, but never learned about "smoothing the bumps". It looks like that will definitely help. I'm brand new to PI, too, having just installed the other day, and working on my first edit - SH2 126 with like 60h of L-Enhance data, so I think this will help with such a faint target.
Thanks again and clear skies.
60 hours! Wow that will be awesome. That target definitely needs a lot of time and will really benefit from GHS being able to bring out the subtle points.
I did just released a part two to this version yesterday which simplifies it a little bit and also covers how to use a different color channels if you want to check that out as well hopefully it helps. It was designed a little bit more beginner, friendly, and with some tips that I’ve learned after using it for several months since making this version.
The log view is super useful. After the initial stretch I go straight to it. I get the peaks of all 3 channels to around 0.06, get the max/mins to be similar and the color match is awesome after the combine which is often damn close to the final result.
Yeah log view is great gives a more detailed zoomed in view of what’s going on 👍🏼
Great video!!! I think this is the best explanation on how to smooth the humps on the histogram and you make it look very easy. Congratulations!! One minor detail, the formula in the description is for the SHO (Forax I believe) and the data you used was HOO where I think you had R=H; G=((O*H)^~(O*H))*H + ~((O*H)^~(O*H))*O and B=O. Clear skies :)
Glad it helped! In that formula, G and B are the same for HOO and SHO. The only difference is R, for SHO it’s another formula somewhat similar to the one for G just with different filters and in the HOO it’s just Ha
Great video! I’ve been struggling with this tool. It takes some practice for sure and a trained eye. So, do you even use STF or HT any more? Also, it’s interesting that you do DBE, SPCC, and other steps AFTER GHS.
Maybe there was a miscommunication because I had already don’t some steps before the video but I would always go DBE and SPCC while linear. For this image since it was a pixel math formula I didn’t need SPCC at the end I just mention some potential steps you can take in a given workflow.
Really great video, amazing what GHS can do!! Love to see it broken out like this, super straightforward. Question - your pixel math expression in the description has the R channel with a reference to S2? I thought you only had Ha and O3 data for this one??
HA is the red channel in this one if you’re doing and SHO send the red channel does have a combination of Ha and S2
For HOO it’s Ha in Red, O3 for blue and a formula of the 2 for green.
Great video... I do things a bit differently.. after the first stretch, rather than look at the histogram first, I look at the image first. Focus on the areas that appear flat, it's way quicker than looking for "humps". It also encourages you to focus on the image rather than the histogram, which is really important in photography generally.
Yeah, I think if you watch the entire video you’ll see that I usually click on the image to see areas that I want to enhance and use that to determine the symmetry point and also look for areas on the histogram. So I do a combination approach to get the best out of both worlds
That way I can use visual cues along with the technical tools we have available. I’m also looking at the image and pointing out the changes in the video while stretching, so taking the visual changes to the actual image in real time to determine. But I am in agreement with you that looking at the image while stretching is obviously very important 👍🏼
Reference 5:32 as an example
A bit different from how others have explained how to use it but I like the way you explained it and why you are doing the adjustments and it all made sense to me. I , being one of those who have used it a bit but went back to the 'older ways' in PI because I didn't have a good feel for it. I want better images than I am getting and I believe GHS will improve my work. Thanks!
That really means a lot. I appreciate the kind words and I’m glad you made the jump back into it, for certain targets, it can really make a big difference!
Great video. Just curious why you don't do any DBE before the stretch? I'm still learning and tend to do that part first, but keen to hear your thoughts why it should be done afterwards?
I do I picked this up after some basic steps. I do Crop > DBE > BXT > NXT Etc
My man!
Best GHS tutorial by far! One question though - is there a reason why you didn't perform DBE/ABE before stretching? Wouldn't the presence of any background gradient interfere with the stretch, given how dim the signal is?
Thank you! BBE right after auto crop and before BXT and NXT. This wasn’t a complete tutorial just focusing in on one portion of the process because it’s not as simple as some of the other steps
Great Job Ryan, I have used GHS a few time but not to the extent you have mainly since I have not seen any good quick videos like yours. I saw Adam had a new video on itr and was planning to watch it as he does good videos but I don't always have time for them so I have to plan them. Question, was this data from monochrome with separate Ha & OIII filters or was it from a OSC with a dual-band filter. Cheers Kurt
These were individual monochrome filters. Thanks for the feedback that was kind of my goal to give more of a readers digest version so people could quickly see how to practically use the tool.
Thankyou
Thank you for being a part of the channel I hope it helped :)
Nice tutorial :) Very enlightend! I have no pixinsight but Siril and bit over 3 hour data from Elefants Trunk, taken with my Nikon D300 and 300mm @6.3 Sigma Tele. Taken in Bortle-6. I know that this is not much data to work on - and maybe all the issue I have... But when I try to follow you along, I get a high "bump" on the left side of peak very early. Instead of right as you show here. Now I'm wondering beacause your slopes on the right. And if I go on, I'm able to iron it out but it looks a bit weird. And end up with a gradually slope from left to right ending with an peak at 3/4 and a cliff.
As I'm new to all this not sure if I do something wrong in the process, need to stretch my data different or its just bad or not enough data here...
Maybe any idea?
I would go for more smalls stretches vs big ones I have google drive if you want to send me a link with the data I can look at it for you 👍🏼
I got a lot out of the fine tuning the curve smoothness and the contrast enhancements. thanks.
Glad it helped :)
I have seen some of your other videos where your process was crop, DBE, BlurX, NoiseX and then the GHS. The end of this video has a different process. Are you doing anything to the stacked image prior to the stretching in this video besides crop?
Same process on this one, I just started at GHS since I have videos with the steps before as you mentioned but the steps leading up to the stretch for me are DCrop, DBE, X’s, GHS, combine, etc.
You can also combine and then stretch. It’s up to you, but I feel like I can get more out of the data if I stretch each one individually, rather than waiting to combine them.
But obviously, if you’re using one shot color, the channels are combined in so you can do the same thing with mono
I’m releasing a video either today or tomorrow where I take a new person through GHS with a color camera and show how to work with each individual color channel on a linear object to stretch them all to get the desired outcome.
I always finish the photos in photo shop and I have a separate video for that process if you want to check it out
At some point I’ll do a full start to finish but it’s going to be a really long video and most people don’t watch for more than about 10 to 12 minutes so I have been doing it in segments
Wondering how to bring out the OIII with a OSC camera and L-eXtreme.
Ok I’ll add it to the docket. I think a new script is coming out soon by the same guys that did the ones on the video I just released on Saturday that will allow you to bring out the narrow band data for one shot color.
If they don’t by the end of the week, I’ll come out with one on how to get some of that individual signal out
Was this shot in Ha Oiii only? In the description the pixel math mentions Sii. I’ve been struggling with learning HOO processing since I got my dual band filter for my OSC cam. I don’t quite have a good way to make my artificial Oiii channel, or a good way to combine them. Any help would be appreciated
Sorry about that. I meant to post the HOO and I think I posted the SHO.
The only difference is just swap the red channel to Ha instead of the formula. I have a video just focusing on my process leading up to and including the pixel math if you go back a couple videos (Magic Pixel Math) in the title.
This one was just focusing on GHS, but that other video has the steps all the way to pixel math.
It also has the HOO formula in the description along with this SHO one.
On my basic workflow stf is first followed by gradient removal. Should ghs be used as replacement for stf? And should it be step 1? Im brand new to the game. Sorry if this is a dumb question.
i had a first play around with ghs just now and i noticed that in your video the tool seems to perform s curves. It doesnt do that when i try it. Any idea why?
Are you setting a symmetry point as I show? If not it won’t do that
This part of the GHS is new to me. I've used this for a month or so now. What numbers are you looking at when you put your cursor over on the image to change the symmetry point? I'm not seeing that. I should also mention that I use a OSC camera, and have done 41.5 hours on this thing and can only pull out about 30% of it...I'm trying your technique now...I'm starting to wonder if maybe a OSC camera cannot do this particular object. I cannot seem to be able to pull out that OIII signal without cooking the red. I'm even adjusting just the Blue channel, and it's affecting the Ha channel...
Thanks!
The latest update fixed all the bugs so I would start there so you have the most recent version.
The method is the same for one shot color, except I will go into each channel of red, green, blue at the very end, and see if I can get a little bit more color out.
The number I am clicking on if you’re talking about how bright or dark the background is if you just click right next to the cursor, you’ll see a decimal come up 1.0 is blown out .00 is total black.
I usually try to match my background and highlights, you can click and drag it around a little area to see what ballpark the average.
If it doesn’t appear right next to the mouse, it will in the bottom center of the screen you’ll see a “K” value that’s what I’m referencing
The big thing I found that was a game changer was going to a dark sky site. I had 15 hours of O3 from my B5 backyard and 4.5 from B2 was dramatically better. So if after you master the technique, you still can’t get the 03 to show you may want to try darker skies if you didn’t do that in the first place.
Yea, I was moving the cursor around on the BG, then when I clicked there I noticed it put the symmetry point on the graph for me, then I sent to SP, then started tweaking...My OIII signal is really weak even after 41 hours. Dark sky would probably improve this. You did a great jog explaining everything! It's no easy task putting together those videos with such clarity! Thanks for the comeback...!
@@rvoykin
Is this about travel astrophotography as well?
It references my trip from 1.5 weeks ago to the Bortle 2 site to get the data for the video. But I don’t travel in this tutorial. I’ll do one travel video monthly after the new moon
Also, was this taken with OSC or monochrome?
Yes, I would like to know too!
I havent reached the end of the video yet but when are you incorporating this stretch? Post SPCC?
You typically want to avoid SPCC for narrowband monochrome images. So I do it after just the initial steps of crop, DBE, BXT, NXT, SXT. I left the stars in for the sake of the tutorial but typically you want to remove them so that you don’t have to worry about blowing the stars out, especially on a faint object like this.
If you are doing any type of color calibration you typically want to apply when it’s still linear.
@@darkrangersinc Thank you! Sorry, i forgot to mention that I will be using a color camera. Thank you for making this video because i have been struggling while using this tool. Ive been trying to produce my comet imagery from February. If you ever want to take on a challenge and attempt my data, let me know ha. Im going to try again here in a month or so and see what i can get.
@@AstroHunter5280 gotcha, that’s why I left a comment at the end just in case because Spcc is great for a color camera. If you want to send it to Darkrangerguides@gmail.com
I’m always happy to take a swing at it…
If you are really struggling, I do one on one time with people, I think in an hour I could save you quite a bit of headache and get you using it really well right off the bat. It’s up to you.
Hit me up on IG (same name) if you want to do that 👍🏼
@@darkrangersinc that would be fantastic. Really appreciate it
@@darkrangersinc when i get home this evening, i will place the data in my one drive and send you over the link. Thanks!
Shouldn´t the stars be removed before stratching? Not to blow them up? Did I miss something?
You certainly can if you want sometimes I do sometimes I don’t for the sake of this tutorial to avoid having to do 2 starless and 2 star images I kept it combined.
The Squid Nebula is a very challenging target and I find that 99% of the time separating the stars isn’t necessary and I’m all about efficiency.
If you watch the second half where I do the bat nebula, you can see the stars aren’t a problem at all and it just saves a little bit of time and ensures the stretch of the stars matches the nebula.
Certainly no downside to separating first and occasionally I do. But especially with BlurXterminator now reducing the stars and not having ti use other methods where separating can be advantageous most of the time I just leave them in.
@@darkrangersinc Yes I am going to buy PI very soon (so far done all with APP and PS). Already have my HSO picture captured but still too hot outside for -10C° darks :-) But yes, I think times are changing and with BXT no need anymore for star separation. I just wanted to hear a confirmation from you. Thanks a lot!
That autostretch looks like my data, im in bortle 6 and have just over 13 hours on it lol
I see you have your image selected in RGB mode in the left menu bar. Why is looking like a Mono? I was thinking we had control over all three channels independently. I'm not having near the success you are and I have 41.6 hours worth of 10 minute subs, Bortle 5...Maybe that's my issue. I need darker sky. I had some moon as well, but was using my L-eXtreme filter. This my second year doing this object. Don't know what else to do to bring this squid out. What do you think?
Oh, I did forget to mention I was using the GHS from the Script menu not the Processes menu...When I used the one from the Process menu, then I had the same GHS screen you did. Script looks different.
And there is a way to darken the BG without clipping the data , I learned this trick from Paulyman Astro...Not sure if you've tried his technique, it works.
I had over 10 hours from my B5 backyard and it didn’t have the same amount of signal as half the time from B2 on a new moon.
The mode I use is RGB for mono, and that’s always going to be what you use, if the data is combined, or you’ve turned it into a color image, you can, then in the mode select red green or blue, and play with each channel individually.
If you watch, my one shot processing tutorial that I put out that too long to go, you’ll see that.
I'll see if I can find that video. Thanks for your Time, much appreciated...!
@@darkrangersinc
Love the start with the M&P-15, haha. Got one hanging in my rack in my office, a 1965 Winchester, and a couple of pistol. My M&P-15 has a Vortex scope on it. haven't had the time to go to the range yet to sight it in...You must be a Vet as well, I was AF 1971-77, a 12-month tour over near Laos on the Mekong during Nam....Thanks again!
Wouldn't be better to remove the stars before stretching?
Yeah in general it is!
I feel like i'm doing something wrong here. When using GHS, I set my SP to a black point in the beginning, set that to the image. I select a part just to the right of the curve and set that to the SP and apply that to the image. When i go to stretch, it's moving the all the data to the right of the SP line while yours is stretching it between that line to the left and right. Am i missing a step? _ EDIT: I think I figured it out, might not have either A) enough data or B) didn't pre stretch enough.
You can do the first stretch without a Symmetry point as well. It’s not 100% necessary and yeah if you have less data I find it better to skip on the first one got for a softer stretch and then just get the local intensity slider at 10-15 pretty high. It’ll look really flat but then you can add the symmetry point in the second and third stretches to add contrast you want to spread out the data in the first one nice and wide so then you can go in and pinpoint different sections
can this work on galaxies?
I Use GHS for every image
why is GHS layout different than yours?, i am updated
I’m not sure… Mine looks like others that I have seen and Dan and I both of the exact same way out even though we have our own version of the software.
You’re actually seen his screen working, not mine, but mine looks exactly the same as his.
If you want to send a screenshot to my Instagram, with the same name, I can take a look at it 🤷🏻♂️
@@darkrangersinc found it, in scripts its different than in process!
I’m currently trying to get the squid and flying bat but using a OSC camera and L-Extreme. Hopefully after tonight I’ll have about 23 hours. The squid is there but not very strong. I tried GHS after watching your video but not apples to apples as you have narrowband. I didn’t get it to be better than my usual stretch. Do you think it’s possible, for someone who knows what they are doing?
I think GHS will outperform a traditional curves transformation, no matter what. My Gmail is rvoykin1@gmail.com
If you want to send me the full size stacked image, I can see what I’m able to do.
Just give me a heads up if you’re going to sign so I don’t miss it in my email. You’ll probably need to do a Google Drive attachment since it will likely be too big to email.
If you don’t mind me, asking, what is the bortle class you’re shooting in, and what is your gear and settings?
I still cannot master this GHS. Frustrating
DM me on Instagram (Same Name) we can set up a 1:1 if you’re stuck we’ll get you unstuck in a one hour session no problem if you like let me know 👍🏼