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.
After Normalization APP generates many statistics on subs, and I am trying to work my way through them to be a little more sophisticated in rejecting weak subs. Previously, I was only looking at star shape.
1) When I select a range and right-click the mouse I have numerous sort options. How is Best to Worst different than Quality?
2) How does APP weight the various measures: #stars/density, background and dispersion, SNR and noise, FWHM min/max shape? Oddly, looking at my Blue data the last five subs had markedly worse SNR rank, but the highest overall quality scores! See attached.
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3) I take it background is brightness. For example, a cloud passes by. What exactly is dispersion?
APP looks at various parameters basically to qualify the data. The quality score is taking into account the star shape quite a bit. So it may score higher there due to very round stars for example.
Thanks for that, it is helpful.
My transparency in the high desert tends to be very consistent. Brightness of course can change a bit during the night. So I suspected FWHM and roundness were the main drivers.
It seems like a good approach. Reprocessing my M31 image dropping the worst 8% of the data made a very nice improvement.
