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.
When I have been using the light pollution tool recently on my Mac, (I have the latest software, the latest APP.)
I get this strange artifact, anyone seen this or have any advice, thx
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Have you tried running a stack without any calibration files to see if the artifacts remain?
I have seen an effect similar to this in the past. But, as I recollect it occurred only when I used the light correction tool on an image that had already been light pollution corrected. Basically the effect is called posterisation.
When APP runs the LPC tool it produces a color correction model that attempts to flatten out the color gradients in the source image. Assuming selection boxes are well placed the tool provides an excellent (but inevitably somewhat imperfect) result.
When the process is repeated, the selection boxes will be placed somewhat differently and the tool will produce a revised color correction model that attempts to flatten out these minor residual variations. Inevitably however there will still be minor residual color variations in the darkest areas.
The posterisation problem occurs when APP is asked to display the highly-flattened 32 bit resolution image produced by the LPC tool, highly stretched, on a computer monitor only capable of displaying color at much lower resolution. The result is the very minor residual color gradients in 32 bit resolution image start to show as steps at the lower resolution of a color image.
So basically I think nothing is really wrong with your image.
Mike
