IC1396 with no stars

[Xplode]

I'm working on a version of IC1396 with HaRGB, but before that's finished i made this version with just Ha and with the stars removed by the software Straton.

This is 177x600s
Total 29,5 hours

Gear
10 Micron GM2000 UP
Takahashi FSQ130ED with 645 0.7x Focal Reducer (f/3.5, 455mm)
Moravian G3-16200

FOV has been cropped a little to remove the halo from a big star

[jjosefsen]

Good job on removing the stars!

I find that some starless images look really "dramatic" for lack of a better word, and this one certainly doesn't dissapoint either.

Beautiful image, thanks for sharing!

[Brian Maurer]

Love all the detail, nice starless image.

[ollypenrice]

Very striking and done perfectly. 

The great thing about a starless image is that stars can be put back into it in natural colour and kept very tiny simply by putting the linear RGB as a top Ps layer (blend mode lighten) and then gently stretching it till the stars begin to appear. I'd love to work this way but, unlike you, I can never get any sense out of Straton!! Any chance of a few tips on how to get Straton to work so well?

Olly

[Xplode]

Thanks for the comments!
I know Straton is supposed to be used on a linear image, but like you Olly i have not much luck...so i used in on the stretched image, works much better and remove just the stars, not the nebula.

[ollypenrice]

19 hours ago, Xplode said:

Thanks for the comments!
I know Straton is supposed to be used on a linear image, but like you Olly i have not much luck...so i used in on the stretched image, works much better and remove just the stars, not the nebula.

Very interesting. I'll give that a try. Thanks Ole.

Olly

[alan4908]

That is an impressive starless image.

I've also had Straton for quite a while but I've never managed to anything useful out of it.  Incidentally, I was recently watching an Adam Block tutorial on how to achieve a starless image using Pixinsight which is based on the process defined by Fabian Neyer. The results are impressive but I think I need to hone my PI skills somewhat before attempting this.

Alan

[glowingturnip]

I've been getting decent results with Straton recently, I use it for tonemap combining narrowband images.  I think the key is to use Straton to produce the stars, then subtract the stars from the image in PI or PS.  It's a bit long-winded though.

Here's what I do, from memory since I'm at work and don't have a Straton screen in front of me:

- works in both linear and non-linear

- open the image in straton

- open the same image again, as the reference image

- set the stretch slider to suit so you can see what you're doing, think it's top-middle ?

- there's a slider bottom right that I think goes from remove more stars to preserve more nebula, or something like that ?  Set it all the way to the right.

- in the menu, remove stars from the image

- then zoom in a couple of times and go all over the image looking for stars it's missed, you can remove them manually, I think there's a clickable tool for that, or is it alt+click on the star ?  Might have to do it 2-3 times on stubborn stars.  The undo tool doesn't work, just makes a mess.

- once done, there's a menu option that says something like 'subtract image from reference image' - do that, and you'll just get the stars and nothing else

- save it and close Straton, then load that star file in PI or PS or whatever.

- zoom in again, looking this time for anything that looks like it's not a star, comparing to the raw image will help, and clone-stamp it out, prevents bright bits of nebula getting removed

- once done, you can then subtract that star image from the raw image in PI or PS.  Key is that 100% subtraction seems to over-do it.  So in PI, use pixelmath and do something like '$T-0.995 * star_image', or I guess in PS you would add the star image as a new layer, blend mode subtract, and opacity 0.995.  Tweak that 0.995 parameter to suit, too low a parameter will leave lighter bumps where the stars were, too high will leave dark bumps, get it just right and they'll disappear.

- you might have issues cleanly removing really bright stars, halos or newt diffraction spikes.