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 use an Optolong L-Extreme with my OSC to gather Ha with RGGB/"Ha-Oiii extract Ha" and O3 with RGGB/"Ha-Oiii extract Oiii" and I also have an
Optolong L-Synergy filter which gathers Sii/Oiii. To produce SHO images I then need S2.
I have tried using the algorithm RGGB/Sulfur II (SII) and combining this result with the Ha and O3 extracted above.
I also tried using "supported/Adaptive Airy disc" to produce a color image and then extract the channels and use the red as S2. i then combine this either with the Ha and O3 as above - or I run "Ha-Oiii extract Color", extract channels, save the red as Ha and average the green and blue from both filters (via Pixelmath) to yield O3.
In all of the cases described above, there is a result but the colors are different.
My questions are:
a) is there one approach that's better than the other - whether more reliable or more faithful in the results?
b) what is the standard way of processing the Optolong L-Synergy in APP?
Tks
Gil
Hi Gil,
I am not an APP expert but I believe the way to process the L-Synergy filter would be to run the extract OIII algorithm so you could combine that with the OIII from the L-Extreme filter. Since there is no extract SII algorithm, I think you just run the extract Ha algorithm. Because you collected SII and it's red like Ha, APP will extract it thinking it's Ha and make a monochrome image of the SII data. You can then combine the Ha, OIII and SII images for a final SHO image. That is how I would do it. If anyone else has a different process, let us know.
Thanks, Tom
Hello Tom,
Tks for the suggestion, I understand your approach.
What holds me back is whether APP's extract-Ha has sufficient latitude to reach 16nm upwards and also grab SII's wavelengths.
I wouldn't know just by looking at the results...
I don't think it matters for APP. It is just extracting the red signal and since the red signal with the L-Synergy is SII, that's what it will extract. I could be wrong but I think I have seen this technique described in other posts.
Tom
Holy smokes!
I just installed beta39 and it seems to answer all my questions: it replaces the old extract algorithms by new "Multi-NB" ones that cover all of my needs (H-a, SII, SII+OIII, etc.)!
Kudos to Mabula!!
Sounds good. I haven't downloaded that yet-waiting for the final 2.0 myself. Good luck.
Tom
Tks Tom,
Indeed, the red channel simply records whatever emission falls in its sensitivity curve. The filter defines the passbands, and the red channel happens to capture SII instead of Ha because of the filter’s design. Since Ha isn’t passed, the red channel contains SII instead.
I was wondering if APP models the filter transmission and camera QE to isolate SII vs OIII more precisely.
Gil
Hi Gilles @museceleste and Tom @tfergu01 & @timjburgess,
Indeed, beta39 has the new algorithms to extract all the different NarrowBand wavelenghts.
I was wondering if APP models the filter transmission and camera QE to isolate SII vs OIII more precisely.
No, it is just like Tom indicates, to get H-alpha or S-II we only need to grab the red channel. There is no need to model transmission and camera QE to achieve the proper extraction of the right data.
Mabula
