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'm still trying to get a handle on interpreting the Star colour graphs and getting good accurate star colour. Trying to figure out how much my light pollution filter is shifting colour?Â
I've attached a screen grab from a recent calibration and trying to understand if I need to do anything additional to the settings, slope/etc? Â
Have I got accurate star colour? Thanks for any help.
Based on that algorithm that seems to be a good calibration yes. The data points are brought closer to the optimal diagonal line which is the expected trend. You can tell that the stars are nicely blue-ish and orange as expected and the H-alpha signal is correct as well. You can play around a bit with that reddish color and make it slightly more pink (which technically is more correct or redder as that's usually perceived as being nicer). In the end there is only the technical correct color belonging to the actual spectrum of the gas and stars, but there's no real "best" color as most is personal preference.
Great, thanks for the feedback.
So in a nutshell if I understand the graph methodology, I want the majority of stars to be along the diagonal, and around 90% or so to be positive, with the remainder negative (blue stars)?
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