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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.

APP - start to finish comparison: M38 and NGC 1907 to NGC 1931 and IC 417

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(@col)
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Joined: 6 years ago
Posts: 127
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Here are two version of 11.25hrs of OSC data on M38 and NGC 1907 to NGC 1931 and IC 417.

First version is APP with a lot of PS editing. However, every time I use PS or PI heavily, I always tend go back to a simpler natural form reversing many editing steps/iterations.

This time, I used the wonderful star reducer (with larger 1.2 and 1.3x factor for star radius and star halo) to reduce to 70% size and 90% intensity. The rest is color calibration, mild selective color enhancement, reduction of saturation threshold to 5% and reduction of saturation to 12%. I used the 20-5-0 autostretch with no contrast or sharpening. The result is the second image.

I worked out really well for an entire APP-only process. In the future, I might test some customized stretch, base and background values. What you do think?

@mabula-admin and friends, i think a slider-variable median filter might be great to add just a little noise/smoothening as a simple start to noise reduction, but I am happy with the APP-only process.

NGC1931 IC417 M38 crop crop lpc cbg SC St ps7
NGC1931 IC417 M38 crop crop lpc cbg SC sr SC St 1


   
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 ah
(@ah_astro)
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Joined: 7 years ago
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Both are nice, but like they are presented now, I choose the first image. Image #2 appears to 'loose' information on the low end of the dynamic range. There's quite some flat area in the histogram (when I load it into affinity-photo). I understand the comparison, in that #2 is meant to be solo APP, but like you already suggest; that is where I would try some customized stretch.



   
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(@col)
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Joined: 6 years ago
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@ah_astro

Thanks. I am in the middle. I prefer the stretching of the background weaker nebulosity and the dust, with the more natural stars (in situ processed) of the latter. These refractor stars, large ones with diffused color are not so easy to mask with such a varied background but starless and star merging in image 1 was reasonably OK. I might try to reprocess like image 1 while keeping the stars in place. However, the test got me a longer way in processing with only app than I ever did before so maybe the extra stretching might be more straight forward. Data from the epsilon 130d is a lot easier to stretch with the small spot size in this regards

Clear skies 



   
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(@mabula-admin)
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Posted by: @cwm2col

Here are two version of 11.25hrs of OSC data on M38 and NGC 1907 to NGC 1931 and IC 417.

First version is APP with a lot of PS editing. However, every time I use PS or PI heavily, I always tend go back to a simpler natural form reversing many editing steps/iterations.

This time, I used the wonderful star reducer (with larger 1.2 and 1.3x factor for star radius and star halo) to reduce to 70% size and 90% intensity. The rest is color calibration, mild selective color enhancement, reduction of saturation threshold to 5% and reduction of saturation to 12%. I used the 20-5-0 autostretch with no contrast or sharpening. The result is the second image.

I worked out really well for an entire APP-only process. In the future, I might test some customized stretch, base and background values. What you do think?

@mabula-admin and friends, i think a slider-variable median filter might be great to add just a little noise/smoothening as a simple start to noise reduction, but I am happy with the APP-only process.

NGC1931 IC417 M38 crop crop lpc cbg SC St ps7
NGC1931 IC417 M38 crop crop lpc cbg SC sr SC St 1

I would definitely choose the APP version (i am so biased 😊 though). The 1st version to me looks very artificial in the nebula parts which I just don't like (for me personally, this is overprocessing yes...) and  the blue stars are more cyan than blue... so the colors in the APP version are definitely better as well.

The APP version lacks contrast when compared to the 1st though, which you could fix most likely with the CON slider in the preview filter, did you try that Colm @cwm2col ?

Noise reduction is soon to be there in APP for linear data.

Mabula

 

 



   
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(@col)
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Joined: 6 years ago
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@mabula-admin 

I also think the APP version is better for this data set, does not show any overprocessing. The first shows what is there in the data, but extracting it shows it needs a lot more time or darker skies. My fast newtonian is a different story, much easier to process faint stuff in APP only. I have played with this version, stretching a little more, but it is touching on the edge of overprocessed again (attached image). And indeed, the color balanced suffered, which is easier to maintain inside APP only.

Although i look at the orange (?) symbol tool tip and examples of sliders with M42 you added to APP help files, can you tell me what the contrast slider works on in the data specifically. I sometime use sharpening and protection, but for star cores that needs to be done very carefully in the absence star masking for example.

I will try to see if the CON can be useful in this case, and I will repost that image too as the 4th and last image of this test.

NGC1931 IC417 M38 crop crop lpc cbg SC St PSv22

 



   
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(@col)
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I investigated the contrast option, as well as further tweaks in APP and settled on this version as an APP only full process. Managing the green using magenta-green HSL selective color variation with reduced saturation, and minimizing saturation for all colors form  0 - background, while balancing magenta-green in star color calibration helped also, negating any need to go outside the program. More data would help with left-over noise, or indeed the noise reducer tool that is coming. It give a nice natural look to the data.

NGC1931 IC417 M38 cropF APP

 



   
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