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.
Hello Vincent, Wouter and Mabula. To my question. How does the quality assessment actually work in APP and what are the steps involved? Do you look at the whole picture or just part of it? I ask because I noticed that the star density is not actually comparable with image shifts (unavoidable with dithering). And wouldn't it be better to specify an area after registration in the light frames that overlaps 100% compared to the rest of the lights. Then the images in the stack can be better judged against each other.
With friendly greetings
Doesn't anyone have an opinion on this? 😟
Hi @minusman,
Quality calculations are revised after each step.
So after 3) Analyse stars, only the star count in the whole image and their median shape (size and roundness) determines the quality score since this is the only thing that we know after that step.
After registration, possible image scale differences are taken into account, so if you shot the data with different camera's, telescopes or sensor binning, APP uses the registration parameters to correct the quality scores that we had after step 3. Furthermore, yes, the registration parameters allow us to use the same area/field of view as the reference frame to correct the other frame scores using the same area as the reference frame area.
Finally after normalization, so images registered and corrected for illumination differences, noise values are also added to the final quality score of the frames.
We will publish the exact formula in the manual that is coming...
Mabula
Hi,
Could I ask a follow up question? I understand that the quality scores of the images calculated by 3) Analyse Stars are used to select the best one as the Reference Frame. Does APP use the recalculated quality scores for the frames in 4) Register or 5) Normalize for any purpose?
Thanks, Jeff
Hi Mabula, thanks for the reply. I just do not know yet which reference range is meant.
1. whole reference frame (green area)
2. or only the area where the images overlap (red rectangle)
Option 2 would have the advantage that one can judge the transparency (by clouds, light pollution, etc.) of the individual frames in relation to the reference frame better on the basis of the star number.
The images above serve only as an example.
Or am I wrong?
With kind regards
