Luminance data - processing help please - data attached LDN1251

[tooth_dr]

Hi.

Last night I got some data on LDN1251, and I'm just trying to get the luminance processed.  I have attached a couple of versions below, and would appreciate any feedback.  Also if anyone has time to process the luminance data so that I can look at the other versions, I would be very grateful, and will try to use this to improve my own techniques.  I'm using PS to process my data.  Version 1 feels underdone, but natural - I want to make the nebula 'pop' more without affecting the stars etc, but I cant manage it.  I want a natural image, but end up with a overdone image - this is version 3 below.  I've added another go, Version 2 below (middle)

 

Raw stacked data attached.  (The guide star was lost and found again at some point during acquisition, but it recentred on a slightly different position - so there are two overlapping panels).

 

Thanks again

Adam

 

 

LDN-1251-Lum-session_1-1.fits

Edited September 20, 2020 by tooth_dr

[johneta]

Are you using a star mask so  the curves have minimal effect on them, -just the nebula?

[tooth_dr]

Just now, johneta said:

Are you using a star mask so  the curves have minimal effect on them, -just the nebula?

Hi John, no I'm not.  I tried a star mask but it left artefacts around the stars.  I think this is the problem, the stars get massive quickly.  Are you aware of any good guides that work for you?

[johneta]

Yes, you've touched on , to me the trickiest part of Processing - Managing the stars.

Ive tried Starnet++ to make a star free image and then work on the nebula only, but I find it has too many artifacts. Others here believe it is great.

I have tried Stratton, an older star removal software which I think is better. But still have to fight with artifacts on massive star fields such as your image.

I have also used Imagesplus masks and star reduction, which I probably like the best, but is a more subtle effect on minimising stars.

Photoshop star minimising is also OK but you can only get a subtle effect from it before you start getting artifacts.

I struggle with them all!

This has pushed me lately into narrowband imaging on my dslr which gives a huge reduction in the star field. This makes it a breeze to process. (except for the other issues it brings up 🤣)

[johneta]

PS, I do like your images. Very nice.

Although..... as we are discussing, those darn stars do get in the way 🙂

[johneta]

If you havnt done star reduction much before, let me know and I'll look up my links on a starter video (Photoshop) tutorial later on my home PC

[tooth_dr]

6 hours ago, johneta said:

If you havnt done star reduction much before, let me know and I'll look up my links on a starter video (Photoshop) tutorial later on my home PC

Thanks John. Please yes share the links. 

[johneta]

You may have already tried this approach, but this is a good starter one to select stars and minimize them

https://www.youtube.com/watch?v=r_kArMKV2UY

then vid 2 in the process

https://www.youtube.com/watch?v=Tr6FM5lCeOw

I dont do his method of color range selection, but instead use Highlights in Color range selection and adjust the range and fuzziness to get a good selection.
Lots of trial and error with all the settings in this method to get it right. So this will get stars minimized but you can only do it subtly.

Another quick way to get a starmask in PS:
Open image
copy the image in the layers window so you have 2 the same.
now on the top layer, - go to filters tab, noise, dust and scratches, and adjust the Radius slider (have Threshold on 5 or a similar low figure) to get rid off all of the stars, and just have a faint glow on the few brightest stars.
Hit OK to complete the Dust and scratches window.
Now on that layer, select blend Mode to be 'Subtract"
You will get an image with stars only. You can flatten the image and you have a stars only image which you can use as a star mask.
Now use it as the mask -on say a curves layer. --Invert the mask so the stars are black and the background is white. (you can also use levels adjustment on just the mask image, in order to increase the contrast between the stars and the background on just the mask-to get a more pronounced effect)
--Then when you boost the curves you will brighten the nebulosity/background and not the stars.
Again lots of experimenting with values at each step of the process is needed in order to practice, and get good results.

 

[vlaiv]

I vote for version #2

[MarkAR]

#2 as well.