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.
[Solved] Interpolation artifacts with Lanczos, Catmull-Rom Spline, Mitchell-Netravali, Cubic B-Spline
I'm getting little bit of interpolation artifacts for the data set that I'm working with.
There are dark pixels at the edge of some stars when I use Lanczos-3 as the interpolation algorithm.
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In fact the artifacts are a lot worse in Pixinsight.
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They are much less noticeable with APP.
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If I use bilinear algorithm, the artifacts go away but the image is not as sharp as one from Lanczos-3(bigger FWHM value).
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I'm wondering if there is a way to preserve FWHM but remove the artifacts.
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Thank you very much.
Donghun
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Hi Donghun,
Yes, I clearly see the artefact. This artefact is known as undershoot. This will always happen with a data interpolation algorithm like Lanczos.
But there is a solution to prevent this in APP. You will need to enable the "no under/overshoot" selectbox below the pixel interpolation filter in 6) INTEGRATE. This should prevent these dark pixels at the star borders due to undershoot.
Let me know if this solves the artefacts with your data.
Mabula
Under and Overshoot happens because a filter like Lanczos has positive and negative lobes see:
