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.
I am currently working on Sh2-86. Star size reduction tool is working great, even on my clunky old Celeron processor, but it helps that my sensor is only 1392x1038.
Even if I don't want to remove all stars, I begin by checking the "Remove Stars" checkbox. That disables all sliders except "Star Radius". I play with that one until I find the desired result. Then I uncheck it and play with the "Star Size" slider. I don't usually touch the other sliders.
In the first attachment, I have 5 hours invested with a 7nm Ha filter. Scope is a 71mm f/5.9 refractor. In the last attachment, I used APP to mix in 2 hours of RGB that I just started to capture. More to go, but you can see that the star colors are nice. So far the nebula is dominated by luminance (Ha) but that should change as I capture more color
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In this image the color is more true to life. I injected a small amount of the RGB data into the Luminance channel instead of relying completely on Ha for Luminance. This made the red "pop".
That's a very nice iteration process you're using, seems to work nicely! I think the updated version will help to get even better results, but very nice! And thanks for the nice comments.
Thank you, Vincent.
I changed strategies. In my previous attempts, I loaded Ha into Luminance, and relied on the RGB stacks to supply the nebula's color. In theory it should work, but it requires LOTS of integration time in RGB. Now I load Ha to Red, which if you think about it makes a lot of sense. However, the problem is star colors. Proper star colors are in the RGB stacks. If I were to simply combine the Ha with the RGB, then there would be an over-abundance of red which skews star colors. The solution is to remove the stars from the Ha stack. Thankfully, I can achieve that with APP 1.083-beta2.
Next step is to combine the nebula and the stars. I used Affinity Photo. (I should look to see if APP can do it, but Affinity seemed to be the intuitive choice.) Affinity has a tool available from the File menu called "New Stack..." (not to be confused with "New Astrophotography Stack...") Afterwards, I cropped it, denoised it, and adjusted shadows and highlights.) That was it!
In this final version, I pushed the contrast to show the luminance variations in the nebula, however, I could only achieve that by applying star reduction to the RGB stack. I reduced them to 40% of their size. There are some artifacts around the stars when you zoom in, but I am very pleased with this result. The proper thing to do is to recapture RGB with a shorter exposure to reduce star saturation.
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