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.
I'm a heavy user of my optolong extreme nowadays which produces great results from my light-polluted and cloudy location. My workflow has been to use APP to extract the Ha-OIII image which I use for stars, and an individual Ha and OIII image for processing (I have tried using the mono as luminance but it doesn't seem to be worthwhile). This workflow takes some time as I'm doing three integrations (usually over >100 images), but I've trusted it's better than doing a Ha=R OIII=G+B on one RGB image and worth the extra time.
However, like many I've just started using BlurXterminator to great effect and the advice is to apply this to RGB rather than mono channels so that it does its magic on correcting any aberrations between channels, so I've been thinking about how to accommodate this. If I run BX on the individual mono Ha and OIII it won't correct for this, also if I run it after I combine HA and OIII, I don't think that will work either as I mix the channels up with palettes like the fornax pixelmath, so any aberration will no longer be clean by channel (I think).
So I've been considering just moving to extract the Ha-OIII image in APP then applying BX then separating out Ha-OIII in pixelmath. Without knowing the algorithmic approach APP uses for dual-band extraction it's hard to tell what I'm losing, so I'd be interested in knowing your thoughts on this.
Option 1 - Use APP to split the channels and miss out on BX aberration fixes
Options 2 - Use Ha-OIII image and pixelmath channel split, and miss out on the value of per channel extraction benefit, but get aberration correction.
What would be interesting is to understand the true value of extracting each channel in APP over integrating one colour image and then splitting the RGB. Can you explain the algorithm APP uses? Is there a big advantage here worth preserving, or is it marginal and I should go for the aberration correction?
Hope that was clear!
-Mark
I extract Ha and Oiii then combine it to HOO, use SPCC and the BXT.Â
/StefanÂ
@digitaliz-se That's broadly what I've been doing, although my combination is a bit more than HOO, often using the fornax palette. My concern is that BXT's handling of optical distortions such as coma and chromatic aberration will be stymied by the fact that I've jumbled up all the channels, so to get this benefit I should use BXT on a clean RGB image, which means I'll have to stop using APP's Ha and OIII extraction and lose whatever benefit that provides over just extracting the channels from an RGB image (which is what I want to understand).
the Ha-Oiii color is the same as extract Ha Oiii and then combine it, but with better S/N ratio.
split the channels after BXT and make your Fornax palette in HOO.
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I personally have no experience with BXT, but the extraction APP uses is a bit more than just extracting the Red channel for Ha for example. I think it also takes some of the green in where it expects some signal as well and extract the signal without injecting too much noise, which would happen if you do this manually. That's about the technical details I know of.
