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.
Hi Mabula (@mabula-admin),
last week I started reprocessing the data of a 3-pane mosaic of the Horsehead Nebula and M42 I made last winter. Each pane is made up from RGB and Ha with a total integration time of ±16 hours per pane. Because the frames are undersampled and dithered I thought it was a good idea to use 2x drizzle during the integration: the stars were originally square, with the drizzle function they get circulair, which makes processing the stacks a lot easier.
In just one of the panes (the one with M42; the other panes are fine) I got some strange artifacts near the border of the stack in all 4 channels when I use drizzle. This doesn't happen when I don't use drizzle. At first sight it looks like the original frames that make up the stack are dithered too well, but that's not the case.
In the screenshots you'll find a stack without using drizzle and a stack with 2x drizzle. Is there any setting causing this problem?
https://www.astropixelprocessor.com/community/main-forum/drizzle-for-mono-cameras/#post-4257
https://www.astropixelprocessor.com/community/faq/bayer-drizzle-and-outlier-rejection/#post-5578
In the two links one finds a good explanation
of Mabula.
I hope it helps.
Best regards.
Thanks for your reply. I tried different settings in the integration tab and now I got a good result. Looks like the LNC settings and/or MBB setting are causing the problem. LNC level 1 with 3 iterations and a MBB setting of 8% was causing the "borders". I decreased the MBB setting to 5% and didn't use LNC at all. Now the stacks are looking fine. In the screenshot the stack of the red data (top) compared to the stack with the artifacts (bottom).
Actually, it's not artifacts at all, it's dithering. This means that the edges of the pixels are not always served with imformation. That's why it looks so holey.
You need a lot of frames and it has to be dithered randomly to counteract the effect. My experience is at least 50-100 or more frames necessary to have an advantage over pixel interpolation.
Thanks for the answer. I certainly hoped to get a lot more data, but as usual the weather last winter was very bad here. I started this project (a 3 pane mosaic of the Horse Head Nebula up to M42 in R, G, B and Ha) early November last year. At the end of February when Orion was disappearing in the evening sky I almost used every single clear night to make this mosaic. I ended up with a total of 533 (good) light frames. Not nearly enough to use drizzle at my benefit.
