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 have access to a multi-session, 4 panel mosiac dataset for M31 with HaLRGB subs. I've (very) new to APP but reviewing the published tutorials, it seems an appropriate workflow for a single session is to integrate the individual panels into RGB and then build the mosiac from the panels.
However, with multi-session data, how does this workflow change? Should each panel be integrated across sessions and then the mosaic built, or, create the mosiac for each session and then stack the resulting panels?
Appreciate tips and pointers to previous posts on this subject.
Thanks, George
@snapthot In APP multiple sessions only are necessary if different calibration data are used per session. If all sessions use the same calibration data then the data can be processed in one session. So if you have, say, L data for multiple nights and you have a set of flats for each night, then you should load the L data for each night in a separate session.
Note that, for APP, data for different filters in general are not considered data for separate sessions. It is perfectly OK to load lights for the L, R, G, B and Ha filters in one session and assign them to their distinct filters. Then you need to do the same with the calibration data and APP will happily integrate them in one go. Note that combining Ha and L data with RGB data (in other words, combining mono and color data) currently doesn't work in APP.
Apart from that, whether a mosaic can be built from the raw data or it is better to integrate the individual panels first largely depends on the number and quality of the raw images. If you have a lot of panels, or if the raw images are subject to light pollution that introduces gradients, then integrating the individual panels first would be a better approach.
As you can see, there are a lot of IFs here. I hope that I was able to help you this way. Feel free to explain more about your data and to ask questions about what would be the best approach to process them if it wasn't.
Thanks Wouter. I was able to get some good results using a slightly different data set (LRGB, no Ha) but still 5 session, 4 panel.
I integrated all panels in 1 session and APP did a nice job sorting it out. Somewhat counter-intuitively, I had to dial back LNC and MBB to reduce banding (1 degree, 5 iteration and 5% respectively). I also had to do a final touch up in Lightroom to adjust black level and mid-range contrast ... might have been able to do in APP but couldn't find a way.
Data was captured on the NYAA Lorenz telescope (130mm Astrophysics Starfire EDF with SBIG ST-8300M). 25 min total exposure on each of LRGB over 5 sessions.
 Overall, I'm pretty pleased.
