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.
Can someone explain why some of my drizzled images, when following the recommendations in the app to use Bayer xtrans drizzle result in a distinctive crosshatch pattern when zoomed in at 100% it's prevalent in colour but more so in monochrome images. Using the non recommended rizzle process does not achieve the same result.
Can someone post an updated video showing how to use the drizzle process properly?
Here are a couple of videos that may help you.
The first one is in German but you can put the subtitles in the language of your preference and it does a good job. Also the images are pretty self-explanatory.
In the second video (in English), it also does an introduction of how to use the RC tool to find out the scale and drop size values depending on the characteristics of your camera and your telescope.
Overall:
Kernel: topHatKernel or SquareKernel.
Droplet size: between 0.7 and 0.9 (in normal conditions)
mode: drizzle if you have a mono camera and Bayer/X-Trans if your camera is OSC.
Scale: around 2.
RC´s webtool:
https://www.rc-astro.com/mtf-analyzer/
First video:
Second video:
Regards...
Thank you but what causes the crosshatch pattern and why does it insist you use bayerxtrans when extracting the Ha or O3 should this not be clearer in the little instructions that pop up?
Still no answer to this question
Bayer X-Trans is only for camerasensors with a bayermatrix, OSC cameras.
Patterns can show up if you have a small number of images to drizzle. The more images the better.
And your images have to be dithered well and often.
@nicholas64 you want to extract and in the intergration drizzle at the same time? I did that but i get squares. The reason i think because its a color camera and not mono, APP is extracting HA and show it up in mono image, while you use bayern in drizzle. That is for color. So i am testing if i need to stack first in color with drizzle and after that load the intergrated file only and do extraction
I’m also experiencing a similar problem with APP in my drizzled image. My setup:
- ASI2600MC (OSC)
- SIGMA 135mm @ f/5.0 (so, well under-sampled)
- Antlia 5nm ALP-T Dualband Ha/OIII
- Zwo AM5
- ASIAIR Plus
I captured a set of 60 subs dithered on DEC and ALT for each frame (10 pixels).
I processed them in APP with the usual master calibration frames (FLAT, DARKFLAT, BIAS).
Kernel: topHatKernel
Droplet size: 0.8 (but tried 0.9 and 1.0 as well)
Mode: Bayer/X-Trans
Scale: 2.0
After following the drizzle tutorial mentioned above and by Sascha from View Into Space, I ended up with a nice image, but there’s a subtle, yet visible horizontal fabric pattern in the background of my stacked image when zoomed in at 100%.
The stars are obviously less pixelated though.
I thought the issue might be due to insufficient data or not aggressive enough dithering, so I shot another set of 70 subs with a 30-pixel dithering distance… same result. I then shot 53 more subs the next night and added them all together (183 subs in total), but I still can’t get rid of that subtle fabric pattern.
Click, it's more obvious in full view:
droplet size <1 is way to small for bayer drizzle. I bdrizzle about 1.5-2.0, you do need much well dithered data too. Best is to test different d-sizes on a cropped integration
@xyfus Thank you for your reply. I’ll increase the droplet size to 2.0 and see what it does.
Not a direct answer to your question, but my recipe in drizzling is Droplet size 0.75 and Scale 1.5. I've sometimes (very seldom) used Droplet size 0.5 and Scale 2.
Been sucessful with lots of setups, including ASI2600MC.
/Stefan
