HDR multiscale transformation question

Gavin1234 · #1 12-10-2018, 07:52 PM

Hi everyone.
I’m have a problem with my Orion core. I’ve taken mostly 300 sec subs plus 20x 10 sec, and 20 x 30. Stacked all 3 groups into 3 stacks registered them, done a very gentle stretch and now I’m trying to do a HDR multiscale transformation to fix the blown core. Unusually this works for me but at the moment I get a bad result no matter how many layers I do.

Anything less than 10 layers gives me a ver rough dug out looking core (see first attachment)
11 or higher blows it out even more (see 2nd attachment).

I’ve tried 2 through to 16 layers masked and unmasked. Any tips?

Karlzburg (Karl) · #2 12-10-2018, 09:16 PM

Star tools has a section to combat blown out cores, maybe play with contrast and brightness on selected area.
See you using photoshop?

Karlzburg (Karl) · #3 12-10-2018, 09:17 PM

Longer exposures from my experience will blow the core out big time.

silv (Annette) · #4 12-10-2018, 09:29 PM

In your last thread you also posted an image of stacked 300secs Orion with an immensely blown out core. http://www.iceinspace.com.au/forum/s...53#post1399153
Someone then suggested you do shorter subs.

So, in order to test your improved, i.e. shortened imaging procedure, you could now try and stack only the shorter subs you took and see what results you get. Leave out the ones with 300seconds from a few days ago.

edit: Would you like to post a single 5 mins frame?

RickS (Rick) · #5 12-10-2018, 09:57 PM

To cope with the very large dynamic range of this area you should integrate the subs of different durations separately and then combine with HDRComposition.

Cheers,
Rick.

Gavin1234 · #6 12-10-2018, 10:48 PM

Thanks guys I probably didn’t explain my workflow very well.

Using PixInsight.
I took 20 x 10 sec subs then stacked those together.
I also tool 20 x 30 sec subs then stacked them.
Finally approximately 50 x 300 sec subs stacked.

So I ended up with 3 images. Then I aligned the 3 images using my 300 sec stack as the reference. Then I did a HDR composition to combine the three into one. Unstretched I can see the core very well so the data is definitely there.

So then a did a very gentle stretch and ran the HDR multiscale transformation but it just isn’t working for me no matter how many layers I use. Funny thing is, I’ve used this procedure before and it has worked but this time around and on one other previous occasion it’s not working. It even worked on one iteration of this image where I messed up the colour. I'm almost certain I'm doing everything up to the HDR MT the same way.

Edit: These pictures might help explain.

The first is the un-stretched core from the stack of 10 sec images, before I did the HDR composition.

The second is the unstretched core from the composite.

The third is my first iteration which is way over processed. I was basically just messing around at this point and didn't save a copy in between the HDR MST working and me completely messing it up.

The fourth is the version Im working on now which is getting close to the colour and detail I want but for some reason I cant get the core right this time around.

Ive started from scratch a few times and tried the HDR MST at different points in the process. Just cant get it working. I think Im probably missing something simple but cant figure it out.

I am planning to reduce my exposure times but in Sydney at the moment its been nothing but cloud and it will be that way for a long time so I just want to process the data I already have while I wait.

Gavin1234 · #7 13-10-2018, 08:24 PM

Finally sorted it out.

Rick kindly used my data on his pc but couldn’t replicate it.

I still don’t know what caused the problem but thanks to a tip from Rick I rebooted my PC and reset PixInsight holding CTRL and pressing R. When I started it back up it worked straight away on default settings.

Still working on my image but I thought I’d write this in case anyone else ever has the same problem and reads this.

Sadly there’s been too much done to my current image for it to work on that so I need to start again.

silv (Annette) · #8 13-10-2018, 08:35 PM

Quote:

reset PixInsight holding CTRL and pressing R. When I started it back up it worked straight away on default settings.

... I thought I’d write this in case anyone else ever has the same problem and reads this.

So true. I wish every user who got something working again would post the solution which solved their problem. Thank you.

RickS (Rick) · #9 14-10-2018, 08:08 AM

I'm glad we got it sorted out, Gavin!