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.
One thing that has been puzzling my mind lately is this:
Assuming imaging a target with faint outer regions where you may only receive one or a few photons pr pixel every three minutes. If you take one minutes frames, the majority of frames this pixel will probably be without photons at all, and some pixels will have one or a few.
How will APP treat the pixels that contains photons? Will these photons be looked upon as outlayers or will they be accumulated even though they do not exist in every frame (pixel)?
@heno Every pixel will contain a value due to read noise and light pollution. Even in the darkest skies on earth possible, the sky background will be much brighter than those faint outer regions so you would need a LOT of images to make them visible. Statistically speaking APP would eventually make them visible but practically speaking you would never be able to because of the number of images needed.
@wvreeven OK, thank you. Even so, at some point in this nebula you will be at a break point where your wanted signal will exceed the background by only a few pixels/time period. But I see what you mean. Neither the censor nor APP will be able to discern between real signal and background/sky fog signal. So in essence all the photons will be taken into account. That is what was puzzling me, but now I've got it.
Have a nice evening. 😀
@heno As a matter of fact, a very faint part of a galaxy will always result into a few more photons arriving at a pixel than the average background. The challenge is the statistical fluctuations in the background that are larger that the number of these few more photons. That is why you need so many many pictures to make those faint parts become visible. OR you need to take very very long exposures so the signal of the galaxy (that doesn't fluctuate) exceeds the (fluctuating) background. Both are challenging if not impossible.
@heno Indeed that's the crux of the imaging signal versus background variance. I can see where the trickiness lies for a given optical system that is trying to pull signal from small faint objects and the possibility that they will always remain either swamped by background signal or never fixed enough with respect to background variance not to be picked off by rejection algorithms. I've tried to pick out smaller companion galaxies before by adding more and more time and just about did it but with horrendous resolution on a medium field system with OK pixel scale!. It gets fixed on larger scopes with longer focal lengths so that faint object takes up more real-estate on a given chip with pixel scale that is possible without seeing limitations and the fixed signal can build up much easier...folks with setups that go after faint fuzzies and small PNs might have the option, not so much for most of us 🙁
