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.
This will probably have a really obvious answer, but I'm a first time user.
I'm working on light frames taken with a DSLR in colour, but when I upload them into APP they shift to green. I can still work with them and stack them, and then take the green away in post, but I've lost all the other colours.
I've opened them as both RGB and incandescent and custom, and it always goes to this green wash.
Am I missing something at the very start?
What camera do you use and did you use any filter? I can look at the data, just upload 10 light frames and your master calibration files for me to check out.
Go to https://upload.astropixelprocessor.com and use upload1 (or upload2 till 5) as username and password will then be the same as the username.
Create a directory named “daraobriain-greencast” and upload in there. Thank you!
@vincent-mod That's really kind of you. I've uploaded the Raw files (there's only 6 of them) and the result I got from the stacking process. I don't think I have a master calibration file (is the dark flats etc? I haven't done them yet, just starting out).
These were taken with a Sony a6000 with no filter. you can probably see the green hue on the result though.
Thanks again!
Thank you, I'll have a look by tomorrow (if the current storm here doesn't damage our internet connection 🙂 ).
So did you any chance to work out why my light frames were coming out green?
this green tint has happened with other shots I have taken as well, despite them appearing normal in Siri, Lynkeos and other programs...
I did! Woops, forgot to actually answer you. 🙁
So it seems the raw data simply has more green in the signal. If I don't stretch and just show the raw data in the histogram, you can see the green channel having its peak most to the right. Also, you should expose for longer as most of the signal is in the noise part of the histogram.
With star color calibration, you can get back to a more normal calibration of the colors, having not a lot of color in the data is likely because you should expose longer and have more data.
Do you use flats?
Cheers, Vincent
@vincent-mod
Thanks for getting back to me! It's hugely appreciated.
That isn't the histogram I'm getting at all though!
If, for example, I look at this picture in Apple photo, of the Hercules cluster
This is how it appears in other software as well.
But in APP when I upload it (RGB channel) it appears like this:
And when I stack, it's impossible to get the colour back.
So what am I doing wrong?
Thank you!
Ok so let's take this step by step to be able to compare the proper things;
At first APP is showing the stretched image in the preview, with this histogram;
Turning the stretching off (deselecting DDP), reveals the data as-is with this histogram;
Now, you can see the histogram is in logarithmic mode, deselecting that checkbox reveals the linear data as-is;
That shows you that the data is very much to the left, meaning a large part of the sensor's ability to record data is not used. Normally you'd want to try and get the signal away from the left at least (say to 5-10% of the range), so that when stretching, the signal is free from the noise background as much as possible.
The other programs probably do some processing to the image already, like stretching and normalizing the image. In my last example APP doesn't, it shows you what you have. You can select normalization on the right where APP will try to normalize the background and it will come closer to what Apple photo shows I think.
Here's the histogram with the DDP (stretch) on again, showing the linear histogram and with normalization on;
That looks more like what you show, so that's the processing the other programs already do and it's not always what you want in astrophotography. There you want to have complete control.
When I turn off normalization, the lineair and stretched histogram looks like this;
That's the data again as-is, but stretched. It shows the offset to green which is in the data. To correct for that you need normalization, star color correction etc and to get proper color, you need more data and to calibrate your data properly with bias, flats etc.
I had to change the star color calibration quite a bit. I think it is because ther are no calibrations done and the stars are out of focus, it might struggle a bit there. But with that and adding some saturation I can still get some color;
That's great Vincent, thank you so much for doing all that; it has really helped explain it. One quick question though... You say to the do the normalization, with a button on the right hand side -is that the "Neutralize BG" checkbox?
Yes, sorry that was what I selected. It's just a preview though, real normalization is done when processing and post-processing.
