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Mar 28 2026 APP 2.0.0-beta40 will be released in 7 days.

It did take a long time to have the work finished on this and it  will have a major performance boost of 30-50% over 2.0.0-beta39 from calibration to integration. We extensively optimized many critical parts of APP. All has been tested to guarantee correct optimizations. Drizzle and image resampling is much faster for instance, those modules have been completely rewritten. Much less memory usage. LNC 2.0 will be released which works much better and faster than LNC in it's current state. And more, all will be added to the release notes in the coming weeks...

Update on the 2.0.0 release & the full manual

We are getting close to the 2.0.0 stable release and the full manual. The manual will soon become available on the website and also in PDF format. Both versions will be identical and once released, will start to follow the APP release cycle and thus will stay up-to-date to the latest APP version.

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Extreme gradient issues with mosaic

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(@tobigh3)
Red Giant
Joined: 6 years ago
Posts: 39
Topic starter  

Posted by: @mabula-admin

Posted by: @tobigh3

Do you think something like this could work?

grafik

 

The issue here would be the middle 2 panels, as they also overlap over the galaxy center, but therefore the other ones contain more sky background.

That would not be the best way for a 6 panel M31 mosaic, because you will still have M31 in all overlap areas especially in the 2 left and 2 right panels., so it will create less issues if you have less of M31 especially in those overlap areas.

 

 

 

Hm I see, but I am not sure how I can prevent that? After all, I want to create the mosaic of M31, so obviously there will be overlaps of M31. Would you mind sharing how I can optimize it?

 



   
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(@tobigh3)
Red Giant
Joined: 6 years ago
Posts: 39
Topic starter  

So, I created the mosaic without the neutralize background option enabled in the Normalize tab, but I still get the same result sadly, so this doesn't seem to be the issue here:

grafik

 

 



   
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(@mabula-admin)
Universe Admin
Joined: 9 years ago
Posts: 5056
 

Posted by: @tobigh3

@mabula-admin 

This is sounding great! Thank you so much for the clarifications. 🙂

 

So, for the integration of teach individual panel, can/should I keep the neutralize BG enabled under 5)?

And then when integrating the panels to the mosaic, I need it disabled, correct?

 

"I know for a fact that the current LNC algorithm is creating your problem partly here."

So, I chose a LNC of 2nd degree with 10 iterations, as I was just following a tutorial. I obviously don't understand any of this, to be frank, I don't even know what the difference between 1st and 4th degree and the different amount of iterations is, so all I can do is following guides here.

Could you just quickly let me know what you think is the best setting here? Thank you!

 

Yes indeed, keep neutralize BG enabled when you make the individual panels and disable it when you make the mosaic 😉

It will be safest and best to use the lowest LNC degree possible, if 1st degree works well, then use that. the higher degree LNC's can become unstable with data like this and this is the main reason to develop LNC 2.0.

Same holds for the iterations, if 1x works well, no need to increase the iterations.

A fast way to test is to use the crop composition mode in 6) integrate, simply select an area (make a crop after having selected the crop composition mode) of the reference frame where the problems manifest, and push integrate and then APP will only create an integration of that part of the data 😉

Mabula

 

 



   
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(@tobigh3)
Red Giant
Joined: 6 years ago
Posts: 39
Topic starter  

@mabula-admin 

Thanks, I will try this in the future. 🙂

However, could you still share how I can set the panels so that it would be good for APP to process? I am not interested in doing many mosaics at the moment, but M31 is my favourite object and it would be a real bummer if I either cannot do it at all, or even worse, spend like 20-30 hours of integration time just to then have issues like this.

Right now I am just testing around so I know how to do it and to see what is working. 🙂



   
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(@tobigh3)
Red Giant
Joined: 6 years ago
Posts: 39
Topic starter  

Hey, can the overlaps be on the fainter parts of M31? Since then I am avoiding the bright center. Something like this with 9 panels:

grafik

 



   
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(@Anonymous 174)
Joined: 9 years ago
Posts: 5702
 

If the overlaps remain nicely covered, than I would say so yes.



   
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(@tobigh3)
Red Giant
Joined: 6 years ago
Posts: 39
Topic starter  

Okay, I just tested it with 3 panels, with the overlap being 20%, and only in the outer parts.

Also, I created the mosaic without the background neutralization.

Sadly, this was also not the solution it seems. While it was already better, the middle panel definitely suffered the most, but the inverse gradients are also present in the other panels. You can especially see it on the darker nebulas, how it cuts off from the right to the middle panel. The middle panel got too bright it seems. This is after light pollution removal:

grafik

 

Unedited, the gradient issue is even more apparent:

grafik

 

Any other ideas on how to set this up?

 

CS Tobi


This post was modified 3 years ago 2 times by Tobias Schwarze

   
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(@mabula-admin)
Universe Admin
Joined: 9 years ago
Posts: 5056
 

Hi @tobigh3,

I think you will need to wait for LNC 2.0 to have this work better on a bright object like M31.

Do you want to share your data with me, so I can use this for testing to improve things in this regard?

If so, please upload it here :

https://upload.astropixelprocessor.com/

username: uploadData

password: uploadTestData

Please make a folder with your name and description like Tobi-M31-mosaic

and let me know once uploaded, thanks!

Mabula

 



   
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(@tobigh3)
Red Giant
Joined: 6 years ago
Posts: 39
Topic starter  

@mabula-admin 

 

Sure, thank you!

I just uploaded my 3 mosaic panels. Each of them was calibrated with Flats, Darkflats and Darks, and other than that was just integrated with the default settings indivually.

The issue just occurs once the mosaic is created.

 

Is there any ETA for LNC 2.0 yet?

 

 



   
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