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.
Whenever I use a dual band filter with x-trans drizzle and extract Ha and O3, I'd really like to understand why I see much much worse drizzle artefacts from the O3. With my setup (undersampled and well dithered) after about 100 frames I'm starting to get good results from the Ha with no noticeable remaining artefacts, but on O3 I'm still having problems with 2x and 3x as many frames. I know I can fix this with more data, but why should I need so much more data to get good O3 drizzle results when Ha is fine with less?
The exposure time is the same for both, so I must be missing something about the x-trans algorithm of how Ha and O3 are extracted which is meaning there's much less coverage of the grid for O3? My understanding is that just because O3 is weak in the target this shouldn't make a difference - the artefacts in the drizzle aren't about how strong the data is, but about how much coverage of the array there is? If it was about the strength then black sky would always show lots of drizzle artefacts.
If I was extracting RGB I'd expect green to show better quality than the others because of the doubling in the CFA, if I understood the O3 extraction algorithm better would this explain the problem with O3? On the face of it Ha should be worse because it's mostly the red channel, whereas O3 is drawing on the other two?
Or is there a bug in APP here I'm experiencing? I'm really puzzled by this behaviour and would really like to understand why I can get great Ha extraction but terrible O3 for the same exposure time. Thanks.
-Mark
