2026-10-09 APP 2.0.0-beta48 has been released !
This is mainly a bug fix release for the reported bugs in beta47. In addition it has a significant User Interface performance improvement noticable when you need to process 1000s of images in APP.
2026-10-03 APP 2.0.0-beta47 has been released !
This is a very big release... many code optimizations/rewrites, many parts of APP are much faster and more precise, especially star analysis and registration are much faster ! Big mosaics will go much faster 🙂
And we introduce a new preview filter, which includes the new Adaptive Deep Sky Stretch and a General Levels Stretch, this has been long over due. The old preview filter (the panel on the right side to stretch and preview your data) has not been updated for a couple of years and it is a critical part of any APP session.
Adaptive Deep Sky Stretch or ADSS is a much more intuitive stretch algorithm. It is also color preserving (which is a great new addition in itself ! ) which means that the highlights are no longer bleached, color is maintained from the linear data while stretching. You can simply stretch your data using the sky background level and signal width sliders which work much easier and more intuitive. You no longer need to fiddle with the old complicated sliders with zoom buttons. All the zoom buttons for the sliders are made redundant. And you can enter slider values in the slider value fields yourself. I will make a youtube video in the coming days to explain and fully introduce ADSS. Once the video is ready, it will be highlighted on the forum.
RGB Combine upgrade !. The RGB Combine Tool has been rewritten mostly. The tool is faster and easier to use and most importantly, the Luminance slider to inject a luminance channel or channels into the RGB composite is now working correctly. It no longer bleaches the RGB colors. Combined with the new ADSS preview, you will get much better and easier great composites with great color! I will also explain this in a new youtube video.
Here's a bit of a strange one. When I merge three panels, I am seeing light appearing towards the edge of panel 2 which when I merge panel 2 and 3 is not there, this only occurs when I merge Panel 1 into the mosaic.
Panel 3 - Top
Panel 2 - Middle
Panel 1 - Bottom
Here's a screenshot of the outcome with all three panels, I am seeing lightness on the bottom right of panel 2 which is not there in the 2 panel mosaic
And same data but just a 2 Panel (Panel 3 and Panel 2) does not show this light at the bottom of panel 2
This only seems to affect the Ha data portion, the SII and OIII seem to be fine, each of the panels on their own also look fine:
Panel 3:
Panel 2:
Panel 1:
I am going to crop the images to remove the stacking edge artifacts to see if it makes any difference, but I have never had to do this before ever, so not sure it will make a difference.
I have tried MBB from 10% to 15% (my overlap is 10%), I have also tried LNC 1/2 with 3 itterations, and it made no difference.
Regards
Simon
try LNC 4 with 3 iterations
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LNC4 itterations 3 made it worse
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It is definitely something within the LNC process as this is the same mosaic without any LNC/Iterations
After further experimenting.
1. If I perform the LNC during the integration of each panel before Mosaic, and then do not perfom any LNC during the mosaic integration, I do not see the issue
2. If I perform LNC during the mosaic integration, this is where I see the issue (whether I've performed LNC on the individual panel stacks or not)
Hi Simon @stastro,
Sorry for my late response here, yes indeed, this is a shortcoming of the current LNC implementation. LNC trys to have the gradients removed or at least blend into each other in the different panels. Apparently, in this case, an articial gradient is introduced to have the gradients blend better, or at least it should. LNC in it's current from is NOT in principal a gradient remover allthough it does it on many cases. If such an artifical gradient is introduced, it can always be removed easily with the Remove Light Pollution Tool, can't it?
For LNC 2.0 I intend to have this work much better.
Mabula
@mabula-admin Yeah, I have not tried the LP removal tool because it is not LP, and the contrast between the two frames (Central and Lowest) is way more than Light Polution artifacts. I will have the finalised data for the lower panel tonight and will re-test.
A quick question though, does LNC make any refference to total exposure time when performing the correction? I have noticed significant differences on panels on my 16 panel mosaic, based on total exposure time, some panels appear darker than others and I tried No LNC, LNC1/3, 2/3, 4/3 etc. I don't have the luxury of obtaining any more data on that mosaic now until June, so work will resume on that next year
Hi Simon @stastr,
Okay.
No, the LNC calculation does not take into account the exposure times of the different panels nor the total exposure time of everything combined. Could the big differences be result of varying sky conditions when shooting those panels?
Mabula
@mabula-admin I thought about that too, however not performing an LNC on the Ha data proves that is not the case, and looking at each of the panels individually seems pretty even illumination across the panels. And the fact this only happens on the Ha panels, the OIII and SII panels work perfectly. Ended up having to run the mosaic through twice, one without LNC and one with as LNC seemed to work well on the OIII and SII data, this was the final image with
Ha: No LNC
OIII: LNC 1/3
SII: LNC 1/3
Hi Simon @stastro,
Okay excellent ! That is an awesome result 🙂
Glad you were able to complete this mosaic successfully !
Cheers,
Mabula
