First Image using PI - NGC7000 widefield

[Clarkey]

I know the North American Nebula is not exactly uncommon, but this is my first image processed in PI - or at least 90% of it. PI is still a bit of a mystery to me, like trying to write left-handed in a mirror...

Anyway, this is just over 6 hours using the FMA180 and an L-extreme filter. I still struggle to get the colour balance I want with PI, but at least this is better than the other processing I have tried. Taken in early September on the only two clear nights I have had so far since the summer.

Comments and advice welcome.

 

[Budgie1]

I've been putting together some PI tutorials to help people get to grips with the basics, I've yet to make one for the workflow I use with an OSC image (next on the list ) but there may be something that'll help in what I've already put together: https://www.youtube.com/@lochaberastro9752/videos

If there's anything specific that your struggling with, then let me know and I'll see if I can put something together.

I'm no PI expert but I know it can be a difficult app to get to grips with, so if I can help with that then it's worth the time.

[tooth_dr]

What a fantastic FOV, I think NAN looks so much better from a wider perspective! Looks a bit green on my monitor, maybe this is the issue you mention with colour balancing?

[Clarkey]

40 minutes ago, Budgie1 said:

I've been putting together some PI tutorials to help people get to grips with the basics, I've yet to make one for the workflow I use with an OSC image (next on the list ) but there may be something that'll help in what I've already put together

Thanks - I'll certainly have a look. I have paid for the Adam Block Fundamentals videos - I'm about halfway through. Very informative if a little slow going.

 

13 minutes ago, tooth_dr said:

Looks a bit green on my monitor

This was not the specific problem - but looking at it again, the lower sky does seem to have a bit of a green tint. What I am really struggling with is getting anything other than red in the NB images. I think I need to work on masking the H-alpha signal in the OIII rich areas. I know it can be done using pixel math - I just need to work out how. At least the weather is so bad I'll get plenty of time to work on the processing!

[bdlbug]

17 minutes ago, Clarkey said:

What I am really struggling with is getting anything other than red in the NB images.

You can look at Bill Blanshan's narrowband normalisation to help with the colour pallete - it is now integrated within PI and he has a very good video on youtube explaining how to install the tool and how the tool works..

 

[Budgie1]

39 minutes ago, Clarkey said:

Thanks - I'll certainly have a look. I have paid for the Adam Block Fundamentals videos - I'm about halfway through. Very informative if a little slow going.

Adam's videos are excellent and I don't claim to know or understand anywhere near as much as he does.  

Mine are very much in the "get you going" category at the moment and I've just uploaded a Basics of OSC processing video, which is currently processing the HD version and will be ready in a couple of hours.  

55 minutes ago, Clarkey said:

This was not the specific problem - but looking at it again, the lower sky does seem to have a bit of a green tint. What I am really struggling with is getting anything other than red in the NB images.

You can remove some of the green cast using SCNR, select Green and use the slider to adjust the amount you want to remove. Just use the Undo button until you're happy with it.

When using a NB filter, in the SPCC process, remember to tick "narrowband filters mode" and set the midpoint for each colour, as well as the band width. For the likes of the L-eXtreme you would use HOO combination:

• Red = 656.30 @ 7nm
• Green = 500.70 @ 7nm
• Blue = 500.70 @ 7nm

[Ouroboros]

That’s an extraordinary image, @Clarkey, irrespective of whether it’s your first go in PI.  It took me a moment to recognise it was the NAN because it’s such a wide field. Isn’t there a lot going on there in the region? Wow!

I’m very interested to see how you progress with this image because I am hoping to do some dual band Ha + OIII imaging myself having only done OSC up till now. I have been watching some videos to try and get my head around how processing of dual band differs and I have to say I as yet don’t have a clear idea of how to go about it. Hoping people will suggest a few more tutorials in response to your post.

What briefly was your workflow to get that image? 

[wimvb]

Very nice. I agree with @tooth_dr regarding the green. Try scnr with its default settings. Once you've subdued the green, the other colours will come through much better. In histogram or curves, you can also target just the blue colour. Subtle adjustments can shift the colour balance.

[Clarkey]

Thanks everyone for all the replies and guidance.  Below is a slightly 'de-greened' image.

8 hours ago, Budgie1 said:

When using a NB filter, in the SPCC process, remember to tick "narrowband filters mode"

I did this for the stars to try and improve the colours - but maybe I need to do this for the nebula too.

 

8 hours ago, Ouroboros said:

I’m very interested to see how you progress with this image because I am hoping to do some dual band Ha + OIII imaging myself having only done OSC up till now. I have been watching some videos to try and get my head around how processing of dual band differs and I have to say I as yet don’t have a clear idea of how to go about it. Hoping people will suggest a few more tutorials in response to your post.

What briefly was your workflow to get that image? 

I've done a fair bit of mono imaging using APP and Affinity. OSC is a different beast that I have not fully got to grips with yet. Dual band even more so.

I don't really have a 'workflow' yet. Press and guess😄. This was more of less BXT followed by SXT. GHS and some colour tweaks followed by a little bit of noise removal then add the stars back. Then there were some final tweaks in Affinity for some targeted contrast and saturation.

 

[Ouroboros]

“Press and guess” I like that phrase.  Sums up my workflow. Actually I’m pretty much OK until I go nonlinear, then I feel I’m flaffing around in a multidimensional space of possibilities. I’m not quite sure where I’m going or how to get there. I always do get somewhere. I end up with an image. But I often feel there’s a better image lurking in the data if only I knew how to get it out. 

[tomato]

Great NAN @Clarkey. I too am from the “Press and Guess” school of processing. There are very accomplished imagers who will understandably frown on this practice, stating that you should know what you want to change on the image and understand the processing tools sufficiently to choose the right one and know what to adjust to make the change happen. The trouble is the software interface is so designed with sliders that it is very hard indeed to resist giving them a try, there is an undo button after all. Even PI, that bastion of rigorous, numbers based processing, allows you to do this.

I don’t think there is any real harm done doing processing this way, as in time you will learn what works and what doesn’t, even if your quantitative understanding of what is going on might lag behind. If I have good data I will always feel there is a better image to be had and sometimes I do go back and find it, but I am much more likely to push mediocre data too far.

Ironically, that’s why I like the Xterminator suite of tools so much, there isn’t much to get your head around with regard to the user interface although what is going on inside the box is another matter.

[Clarkey]

1 hour ago, Ouroboros said:

But I often feel there’s a better image lurking in the data if only I knew how to get it out. 

 

16 minutes ago, tomato said:

If I have good data I will always feel there is a better image to be had

This is my issue. I get images, but I feel there should be more.

I think maybe I am being a little unfair on myself with the 'press and guess' description. However, often I know what I want to do, but cannot always get there. To be honest this is true for all the software I have used - not just PI. However, the PI interface is far from easy to use. I will keep working with it though as from my experience so far, I do think it has the potential to produce the best images. It's just the clown working with it that is holding it back😂

[teoria_del_big_bang]

1 hour ago, Ouroboros said:

“Press and guess” I like that phrase.  Sums up my workflow. Actually I’m pretty much OK until I go nonlinear, then I feel I’m flaffing around in a multidimensional space of possibilities. I’m not quite sure where I’m going or how to get there. I always do get somewhere. I end up with an image. But I often feel there’s a better image lurking in the data if only I knew how to get it out. 

 

55 minutes ago, tomato said:

I too am from the “Press and Guess” school of processing. There are very accomplished imagers who will understandably frown on this practice, stating that you should know what you want to change on the image and understand the processing tools sufficiently to choose the right one and know what to adjust to make the change happen. The trouble is the software interface is so designed with sliders that it is very hard indeed to resist giving them a try, there is an undo button after all. Even PI, that bastion of rigorous, numbers based processing, allows you to do this.

 

26 minutes ago, Clarkey said:

This is my issue. I get images, but I feel there should be more.

I think maybe I am being a little unfair on myself with the 'press and guess' description. However, often I know what I want to do, but cannot always get there. 

I do hear similar comments on SGL quite a lot and the same goes for myself to a certain extent. A few images lately (I say lately probably Feb/March as not done any imaging since due to weather and commitments) I seem to have got the image I want first attempt but others I do seem to faff about constantly tweaking till the image is useless then going back to linear stages and starting again and often I get an image but one that I am never really happy with.
Now, for me at least I think I may know why and the few images that came together really quickly first time look like most other images (or what I consider to be good images) of the targets, with similar colours and saturations, the details are there (to some extent anyway) that I can see on other good images and somehow that makes me satisfied I have done a good job. 
Now, the other images I struggled with do not have this quality, and no matter how much I try to go back and start again, no matter whose tutorials I follow (and  @Budgie1 some great ones there on your link) they still never really do end up as I want them.
Why, not really sure but probably the detail, or at least the detail in some of the filters (RGB or SHO) is just not there, or the seeing was just not great, or I was just wrong with exposure length or something.

The other thing to consider is that at the end of the day we generally are creating an image that is not true to what our eyes see anyway. They are not really false images if we process properly as everything in the image should be something that is actually there and on our individual images but the colours and the ratio of how we mix them, that is not true at all, but we probably become fixated on other images, maybe even harking back to Hubble's perspective on Space, and then feel those colours are what we should be producing.

Well that's sort of how I see it anyway but my wife and kids often say I talk nonsense so still may be the case 😂, also I think generally images are very self critical and too harsh on their own work.

After all that waffle, @Clarkey that actually is a great image and I agree with the fact how this target looks so much better widefield like this rather than just a magnified section most images are, given some good weather I would love to do a mosaic of this area of sky.

Steve

Edited October 4, 2023 by teoria_del_big_bang

[ollypenrice]

I'm impressed by the image. It's strongest feature, for me, is the way it distinguishes between different levels of very dark, sooty dust. Often they are all clipped down to the same level but here they lie in clearly distinguished layers.

What I'd want to work on would be getting it less monochromatic-looking. Most of the image is the same colour. I think this is largely a result of the filter cropping the blues. One thing to try would be increasing the contrast in the blue channel.

Regarding playing with ill-understood sliders, I do try to avoid it and we all do it to some extent, no doubt. Just don't make an instructional video saying, 'This is me thrashing about with sliders I don't understand and hoping to find something I like!'  There are way to many of those videos already...

Olly

[tomato]

In a previous life I was often required to do training presentations on a whole variety of topics which for the most part, was quite enjoyable. What I didn’t like was presenting on a subject which I knew little about, even if my audience knew even less. I have heard the adage about the one eyed man in the kingdom of the blind, but I always felt I was on a rickety rope bridge and my next utterance would send me crashing onto the rocks below.

[Clarkey]

15 minutes ago, ollypenrice said:

Just don't make an instructional video

No chance - camera shy and incompetent. Not a good mix🤣

[clarkpm4242]

Lovely field of view!

I'm a fan of good composition in deep sky images.

Paul

[ollypenrice]

9 hours ago, tomato said:

In a previous life I was often required to do training presentations on a whole variety of topics which for the most part, was quite enjoyable. What I didn’t like was presenting on a subject which I knew little about, even if my audience knew even less. I have heard the adage about the one eyed man in the kingdom of the blind, but I always felt I was on a rickety rope bridge and my next utterance would send me crashing onto the rocks below.

Yes, in my previous teaching life I always felt that, when required to take charge of a classroom in which I was not properly informed, the best place to start was, 'I don't know about this, so let's try to find out.'

Olly