Looking for some help

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Troy Galebach
Posts: 39
Joined: Fri Dec 28, 2018 8:31 pm

Looking for some help

Post by Troy Galebach »

I have this image of the Lagoon Nebula, it isn't that good, but it might be better if I could get rid of 1000s of dim stars in the background.
Any help will be appreciated, and thanks in advance for your input. I hope there is an easy fix, so I can fix all the other problems present in the image.
Regards,
Troy Galebach
Image
Startrek
Posts: 138
Joined: Mon Dec 30, 2019 3:49 am

Re: Looking for some help

Post by Startrek »

Troy
Your image of M8 is fine
The Star field in this image is normal but to lessen its affect on the whole image can I suggest you concentrate more on the nebula itself
If you can make the nebula the centre of attention, then the Star field will be less noticeable ( In others word try to make the nebula “Pop” )
You could use various tools to reduce the Star field but personally I’d go for giving the nebula itself more dynamic range / detail and brightness etc..,

Some details on your capture would help ….,
Scope
Camera
Any filters
Subs
Calibration frames
Stacking software

Is this image RGB ?

Cheers
Martin

As I mage at 1250mm fl , tools like Shrink and Super Structure ( Isolate and dim small ) help to lessen the impact of a Star field but not sure how they would go at your focal length ?
Troy Galebach
Posts: 39
Joined: Fri Dec 28, 2018 8:31 pm

Re: Looking for some help

Post by Troy Galebach »

Martin, thank you for your input, I have been fighting this issue for some time. I don't know if I've responded correctly to your reply, but I hope I have. I am a stroke victim, so I don't always do things correctly when on this and other Boards.
Startrek wrote: Thu Jul 21, 2022 2:16 am
Some details on your capture would help ….,
Scope Takahashi FSQ-106 fl 530mm
Camera Mallincam OSC video camera DS16C-TEC (cooled)
Any filters No filters
Subs 50 frames @ 20seconds
Calibration frames Yes Flats, Darks, & Bias
Stacking software Siril

Is this image RGB ? Yes

Cheers
Martin

As I mage at 1250mm fl , tools like Shrink and Super Structure ( Isolate and dim small ) help to lessen the impact of a Star field but not sure how they would go at your focal length ?
I did use Isolate to dim the starfield, what throws me is comparing what I ended up with, as to what others end up with. I process on Linux, and so I don't have all the fancy tools some other folks have in Windows. I suspect someone will program those tools in the near future, but for now it is Siril, StarTools, and RawTherapee for me.
Thank you again Martin, I hope this post shows up where you can see it, and more importantly if it answers the questions you've asked.

Regards,
Troy
Troy Galebach
Posts: 39
Joined: Fri Dec 28, 2018 8:31 pm

Re: Looking for some help

Post by Troy Galebach »

Martin, is this more like what you envision?
Image
I honestly don't know if I've done any better, I will leave it to you to decide.
I do note a difference between the requested .jpg file and the one I see on my screen, the conversion between .tiff and jpg takes a lot away.

Regards,
Troy
fmeireso
Posts: 132
Joined: Mon Sep 28, 2020 8:46 pm
Location: Belgium

Re: Looking for some help

Post by fmeireso »

Troy,

Superstructure - isolate but set the Brightness retention to local median, otherwise by reducing the stars the nebulae might a bit lost too. Also you could run it multiple times. On very busy starfields i sometimes run it 3 times ...

Other then that Shrink might also be of help as here allready being mentioned

CS
Freddy
Troy Galebach
Posts: 39
Joined: Fri Dec 28, 2018 8:31 pm

Re: Looking for some help

Post by Troy Galebach »

Freddy, thank you for your response. I've used StarTools for years now. I didn't realize I could use the SuperStructure module more than one time. This is what happens when you are 73 and have suffered 2 strokes. Thank you!
fmeireso wrote: Thu Jul 21, 2022 4:56 pm Troy,

Superstructure - isolate but set the Brightness retention to local median, otherwise by reducing the stars the nebulae might a bit lost too. Also you could run it multiple times. On very busy starfields i sometimes run it 3 times ...

Other then that Shrink might also be of help as here allready being mentioned

CS
Freddy
Startrek
Posts: 138
Joined: Mon Dec 30, 2019 3:49 am

Re: Looking for some help

Post by Startrek »

Troy,
Good on you for taking up such an incredible hobby after having some health set backs
There are a lot of folk who have all types of health problems and still enjoy our hobby
Wonderful !!

A couple of suggestions
Maybe try to take 30 , 40 or 60 sec subs next time if your mounts tracking and polar alignment will allow such durations. Plus try and capture more data. All of us can never have enough data
The more data you capture the more Startools can weave its magic
It’s not recommended but you can use Super Structure more than once, I certainly do ( isolate and dim small etc.. ) however I do use a Star mask always with most modules to isolate my stars so they don’t bloat during the process

Hopefully more integration time will allow Startools to make the object “Pop” after a stretch
Also I never use FilmDev to stretch as has no control over the main structure of an object, it just does a uniform stretch across the whole image which blows out everything including stars
AutoDev is the way to go , set a ROI around your object and play with ignore fine detail and shadow linearity etc…

Cheers
Martin
hixx
Posts: 185
Joined: Mon Sep 02, 2019 3:36 pm

Re: Looking for some help

Post by hixx »

Hi Troy,
A lot of techniques have already been covered, let me sum up some strategies to enhance nebulas vs stars in :
1) Use a Duobandfilter for Luminance (e.g. Optolong L-enhance, IDAS NB-1, Altair Tripleband/Quadband)Such filters were designed exactly for that purpodse: enhancing Nebulas vs stars, so You'd start off with an image much closure to what You want and less need for Post-processing magic.The filter will dampen the stars during capturing, allowing for less bloating stars or longer exposure.
2) To achieve true star colors, take a second exposure using a clear or an UV/IRfor RGB stack, as the Lum stack will have incorrect color data with missing wavelength (lacking yellow stars). Please note You will need new flats for each filter in each session.
3) In ST, develop BAU for details. Use the SVDecon module to achive pin-point stars by selecting a number of sample stars in all regions of the image
4) After Color use Shrink Module with the default preset (Tighten Algorithm)
5) Use SuperStructure Isolate or DimSmall. As already mentioned take care of the brightness retention setting

Clear Skies,
Jochen
Troy Galebach
Posts: 39
Joined: Fri Dec 28, 2018 8:31 pm

Re: Looking for some help

Post by Troy Galebach »

Martin, thank you for taking the time to provide input to a guy who needs it. I've come to the conclusion that I need all the automation I can get while collecting that data. I have set up N.I.N.A. to help with that process. I have an iOptron CEM40G mount, and have gotten guiding working, along with using their iPolar for my PA. This image is the result of my first capture using N.I.N.A. I also captured M20 but it wasn't nearly as problematic as the Lagoon. I will never be great at this, just a fact, but I may improve the outcomes thanks to you and others who've taken the time to reply to my request for help.
I will certainly take those longer exposures now that I know things were working as expected. I could bore everyone to tears with the list of the times they didn't work as expected. Then there was the time I took my brand new iOptron mount out, and while setting it up, knocked the head off the tripod and ruined it because it fell on the cement. It was trashed, but the wife told me to order another one. That's why I've been married for 52 years to that woman.

Your tip on AutoDev is useful, as I've always used Film Dev. I'll begin implementing that immediately. I know I can get exposures at 300 sec, never tried beyond that. I'll use 60 sec my next trip out. If you are interested.....https://tgalebachmo.net/astronomy/.
Thanks again Martin.
Regards,
Troy
Startrek wrote: Fri Jul 22, 2022 1:36 am Troy,
Good on you for taking up such an incredible hobby after having some health set backs
There are a lot of folk who have all types of health problems and still enjoy our hobby
Wonderful !!

A couple of suggestions
Maybe try to take 30 , 40 or 60 sec subs next time if your mounts tracking and polar alignment will allow such durations. Plus try and capture more data. All of us can never have enough data
The more data you capture the more Startools can weave its magic
It’s not recommended but you can use Super Structure more than once, I certainly do ( isolate and dim small etc.. ) however I do use a Star mask always with most modules to isolate my stars so they don’t bloat during the process

Hopefully more integration time will allow Startools to make the object “Pop” after a stretch
Also I never use FilmDev to stretch as has no control over the main structure of an object, it just does a uniform stretch across the whole image which blows out everything including stars
AutoDev is the way to go , set a ROI around your object and play with ignore fine detail and shadow linearity etc…

Cheers
Martin
Troy Galebach
Posts: 39
Joined: Fri Dec 28, 2018 8:31 pm

Re: Looking for some help

Post by Troy Galebach »

Thank you for your advice Jochen. You might have read my response to Martin, where I dropped and trashed a brand new iOptron head. I suffer from palsy and trying to put things together with threads, screws, etc. is almost impossible for me. Especially true after the sun has set. If I can mount the filter to the camera before I head out, it's doable. I had been considering filters, but frankly, I didn't know if I'd be able to continue this hobby. I hope to figure that part out in the next several months if the weather cooperates. I've only been out 2 times since early Dec. 2021.
I use a OSC because anything with more parts and complexity would be a circus here, and nothing would ever get done, I'd be the head clown. I have to set up each time I go out. I have a storage shed, but only the mounts stay in it these days. I'd never get to imaging if I went with LRGB imaging ;).
I don't know what "develop BAU for details means" Sorry could you elaborate? I've tried to use the SVDecon module but haven't noticed a large difference between what I get using that, and the previous versions of StarTools. I'll read the manual more, it is likely me doing something wrong.
Thank you again Jochen, my take away will be to try the Optolong L-enhance filter. Oh and to look for what BAU means.
Regards,
Troy

hixx wrote: Fri Jul 22, 2022 6:02 am Hi Troy,
A lot of techniques have already been covered, let me sum up some strategies to enhance nebulas vs stars in :
1) Use a Duobandfilter for Luminance (e.g. Optolong L-enhance, IDAS NB-1, Altair Tripleband/Quadband)Such filters were designed exactly for that purpodse: enhancing Nebulas vs stars, so You'd start off with an image much closure to what You want and less need for Post-processing magic.The filter will dampen the stars during capturing, allowing for less bloating stars or longer exposure.
2) To achieve true star colors, take a second exposure using a clear or an UV/IRfor RGB stack, as the Lum stack will have incorrect color data with missing wavelength (lacking yellow stars). Please note You will need new flats for each filter in each session.
3) In ST, develop BAU for details. Use the SVDecon module to achive pin-point stars by selecting a number of sample stars in all regions of the image
4) After Color use Shrink Module with the default preset (Tighten Algorithm)
5) Use SuperStructure Isolate or DimSmall. As already mentioned take care of the brightness retention setting

Clear Skies,
Jochen
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