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
I used the Star Collar Calibration Tool for the first time. The image is at that time.
I am not understood by the following point. I'm glad if I get advice from someone.
1. What are the graphs propose to me?
I understand that it represents the distribution of stars
2. What I make a basis of adjustment of BLUE-RED SLIDER, B-G VERSUS G-R, B-R VERSUS G-R ?
 Thank you
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I would advice to have a look at these video's by Christian Sasse: https://www.astropixelprocessor.com/complete-lrgb-tutorial-of-ngc292-the-small-magellanic-cloud-by-christian-sasse-itelescope-net-new-version-app-1-081/
Bit further down he works with this tool. It basically shows you the distribution of detected stars and their color profile, it assumes stars are black bodies which will have a very well defined profile. You would want to see the stars following this black body model well, which is diagonally in the graphs and you can tweak this using the sliders a bit, like the slope etc.
One caveat though is that this only works well with broad spectrum data, not narrowband.
@vincent-mod
Hello Vincent
I had a look at these video's by Christian Sasse.
I understood that the graphs do not just propose a proper color, but simply shows the color distribution of the stars.
Does I make the stars red or blue are decided by my subjectivity or sensitivity?
The graphs change by changing Slope, but how can I determine if the Slope value is appropriate or not?
Thank you
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Yes it's color distribution and you expect stars to be more or less on the line of the model, less blue stars on the bottom left, more red on the top right. These are known spectra and not subjective. If your stars are not behaving like that in your image, that means you either used filters or other things that change the spectra observed. This is why narrowband data doesn't produce this known characteristic and therefore the tool can't really be used for an accurate correction. When you do have broadband data, then you can. You can change the slopes a bit so that the distribution of the stars follows the black body model a bit better. You can see Christian doing this at about the 16:00 mark.
My image is a broadband, so I think it is suitable for this tool.
"You Can Change The Slopes A Bit So That The Distribution of the Stars Follows The Black Body Model A Bit Better."
I try to change the slope so that.
Thank you
