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 everyone, I have watched Manila’s video on HSL Selective Color and I have figured out some of it, but I wish I knew what colors come from moving certain sliders. For example, let’s say I want to make my orange stars more saturated, what would the slider choice be for that and which color would I select? I guess there is a theory to how HSL color works. I love APP and slowly I am getting better with it. Thanks!
Greg
@astrohound24 Greg, your particular question about stars only is a hard one since APP currently doesn't allow for that. Also, HSL Selective Colors isn't so much for color saturation but more for changing the color space. In some cases this difference may be subtle but it is important.
If you want to make more orange visible (meaning convert similar colors to appear orange) then in HSL Selective Color you can select the ALL color channel.
Next you select a range. for adding more orange a possible choice could be "background - 75% of range" or one of the "background + X*noise - 75% of range" selections.
You can then adjust the selected range by using the LOW and HIGH sliders.
You can click the "show color selection" button to show which pixels will be selected. For instance, on my image of NGC 7000
selecting "background + 3*noise - 75% of range" shows this selection:
Once you're happy with the selection, you can move the R<->CY and G<->MA sliders both to the left by, say, 30% and click "calculate current adjustments". In my case I get this:
Note that when you use the LOW and HIGH sliders, you'll need to click the "show color selection" again to show the newly selected pixels. APP doesn't automatically update the view.
I hope this answers your question.
Wouter
Yes this helps. Thanks! When selecting backgrounds I guess one can experiment by checking which selections show which pixels will be affected by looking at the show colors selected tab. I was just trying to make my orange stars more saturated and blues, etc. Thanks again.
Greg
One more question. If HSL color is more for colorspace than about saturation, what is good way to increase saturation of something like the brighter stars in an image or anything in the image for that matter? Thanks!
GM
@astrohound24 The saturation slider in the tools section on the right hand side of the APP window would need to be used for that. APP doesn't have masking capabilities to only adjust the saturation of the stars, however.
