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. My camera is ZWO ASI294MC Pro. Having an issue with "Extract Ha" algorithm. The image was taken with HaOIII filter. After integration, if I zoom in I'm seeing weird patterns. This only happens with Bayer Drizzle, in this case 3.0 but can happen with any scale. If drizzle is off there's no pattern. Also no pattern in colour images, regardless of drizzle setting.
How to fix this pattern?
Attached is the example
- Top left is "HaOIII: Extract H-alpha" with drizzle disabled.
- Top right is "HaOIII Mono" with 3.0 bayer drizzle
- Bottom left is "HaOIII: Extract H-alpha" with 3.0 bayer drizzle
- Bottom right: "HaOIII color" with 3.0 bayer drizzle
And finally the image of the pattern I'm having issue with. Why isn't it "solid" colour?
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I see the same thing. Extracting without drizzle or doing Ha-OIII color with drizzle works, but extracting with drizzle gives that pattern and/or doesn't result in different Ha and OIII outcomes.
How did you capture the data? It is important for drizzling that your data is undersampled (or at least it will have a good effect on that) and very well dithered.
What counts as sufficiently under-sampled or "very well dithered"? I can say that I'm what astronomy.tools would call slightly under-sampled at 2.24"/pixel. For dithering, I used 1 pixel dithering (and I have the option to use 2, 3, 5, or 10) after each frame and required 1" stability to start again with a 5s settle time.
I'd say that somewhat undersampled can already benefit from it, regarding dithering I would go higher, probably at least 3 as that will then cover more pixels for it to do the drizzling with. The more data the better for it as well.
Dark and brighter grey-scale pixels are alternating in a specific pattern in each line:
D B D B D B D B...
B D B D B D B D...
D B ...
I thought it has something to do with de-bayering in combination with drizzle, or maybe there's some other reason. While dithering is important it's not relevant to producing such a pattern in the image.
I confirm what Roman had said: extracting OIII or Ha from HaOIII-filtered colour image plus drizzle with result in this alternating pattern of pixels instead of a smooth image.
Also the Ha-extract and OIII-extract are the same image:
https://www.astropixelprocessor.com/community/main-forum/duo-band-l-enhance-and-drizzle/#post-12492
Yes, I'll have a look at the data today, it might point to why this is the case.
