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,
I have a hard time using drizzle (mono) with a set of 75 frames. I get weird kind of "bayer - pattern" like in the background.
I used the following settings : droplet 0.5 scale 2.0. Note that I usually use these settings without 0 trouble and that for another panel shot in the same conditions and about the same number of frames as the problematic set I get excellent drizzling results.
I tried to up droplet up to .85 and it seems to be back on track.
Is there a way to pre-determine the right droplet on a given set or it is more an iterative approach?
Any advice I should be aware of?
CS!
Axel
Not really to my knowledge (going to 0.5 makes sense, but it does have the best result when you're undersampled), can you post a screenshot of the other panel that did work nicely? Just for me to get a better idea..
Not really to my knowledge (going to 0.5 makes sense, but it does have the best result when you're undersampled), can you post a screenshot of the other panel that did work nicely? Just for me to get a better idea..
Dear Vincent,
As for the 0.5 droplet I use it as refered in the help box :" droplet.5 with scale x2 is similiar to drizzle in other software" (thinking of PI I guess).
If you have a good guidance as how to approach drizzling at 4.4"/px, I'll be happy to adjust my processing.
Here is another panel with 0.5 / x2 that came out clean
BR,
Axel
Yes, so that's why the 0.5 is kind of a good starting point. I'm not sure if it works well on your pixel-scale, I'll ask Mabula to answer here. 🙂
Hi Vincent,
Any feedback from Mabula?
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Hi Axel, not yet sorry, busy times. I've notified him again.
Hi Axel @axel,
I think that the pattern that you are getting is clearly due to drizzle artefacts... and if the drizzle droplet size increase solves it, it is confirmation that the artefacts are due to incomplete drizzle... So it likely means that
- the data is not enough dithered or
- the amount of data is still to small or
- the data is not that undersampled this time due to very bad atmospheric conditions possible... (seeing of 4-5" does occur on bad nights).
How much did you dither between the frames? How are the star sizes compared to the other datasets?
If on other datasets with the same amount of frames the artefacts are not there then the reason must be somehow in the data itself. Drizzle will only work nicely if all 3 drizzle conditions are satisfied 😉
What you could do as well, do not drizzle in this case, simply set scale to 2.0 and use data interpolation if you want the higher resolution. It might work better than drizzling on this particular dataset.
Another thing that you could try, is to alter the drizzle kernel. Which kernel did you use? It is mentioned in the FITS header of the stack.
Mabula
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@mabula-admin Hi Mabula,
Thanks for your feedback.
I try to answer your points
dither : I use unguided tracking but in SGP I use Direct Mount Guider set to a dither of 1sec impulse every 3 frames . Never get walking noise doing so but may be it is not enough for drizzle.
number of frames : 75 in this case over 5 nights
quality of the panel wrt to other panels  : I randomly picked 3 frames from each night of this panel and ran star analysis and compared to 3 frames from each night for another panel (I shot 4 panels a night). I've got close results in terms of data shape.
seeing : can't tell tbh.
Best
Axel
