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 know that APP can extract Ha and O-III from dual-band pass filters like Optolong L-Enhance - I'm using that effectively.
However, I'm not sure that the same technique would apply to extract separate channels from triband filters for OSC in heavily light-polluted areas, such as Antlia's Triband RGB Ultra 2" Filter (which isolates Ha, S-II,O-III and N-II).
If not, how would I go about it (knowing that the results will never be as convincing as using true narrowband on a mono camera)?
Tks
@museceleste no you cannot, and its not APP’s fault.
Ha, Nii, and Sii, are all in the red part of the spectrum, and using an OSC, the bayer filter of the camera passes ALL three wavelengths through ONLY the red pixels of the filter. Oii and any Hbeta are in the blue and green part of the spectrum, and the camera bayer filter passes these wavelengths into the blue and green pixels. So by the time APP can read the pixels to convert the raw file into colour, the light from the individual chemical elements are already mixed, and cannot be separated out.
no software can do it I’m afraid. The advantage of these tri and quad band filters over the duo , is only that the red, green and blue signals are stronger ( more total light transmitted) , with a better Signal to noise ratio, than their duo counterpart.
to get individual chemical transmittance, you have to have single channel filters, and ieally a mono camera.
Thanks so much, Andy. You hit the nail on the head, with the Bayer matrix. Currently, I find a bit too weak the blue captured by L-enhance. I interpreted Altair’s filter triband and quadband designs as being able to slightly augment the capture of red by combining Sii with Ha and augment the blue by combining Hb with O3 - and thought that this could perhaps improve my dual-band pass photos. However, I was unsure if the APP extraction would still work. But with your point on the Bayer. APP should still see hydrogen and oxygen (albeit perhaps a little stronger) and the extraction should still work, right?
Hi @museceleste and @andybooth,
Andy's answer is excellent, I have nothing to add to that.
In this, case, the Ha-extract algorithm will simply extract the combined signal of the narrowband signals that the Triband filter passes, so at least you can subtract that. And the same holds for the O3 extract algorightm. Afterwards you can still create a Bi-Color Ha-O3 like composite I would think 😉
Mabula
Thank you to both of you and have clear skies!
I have a LExtreme 7nm duo which I use when the object is bright and with a lot of fine detail, or the moon is very full.
I also a Baader UHC-s filter which is like a quad band as its bandwidth also passes sii and Hbeta, with a bandpass of about 60nm, which I use when skies are darker and on fainter objects, the difference in transmittance between the two is very marked.
in theory, duo should give better definition, but with my seeing of 2-3”, I dont really see a difference.
with the duo I have to do 360s exposures, whilst with the UHC (quad band) I can do 180s exposures.
andy
Hello Andy,
That's nice of you to add to this. In my case, I live under a Bortle 8 sky and the only two ways I found to fight the light pollution was to use dual band filters and (recently) to convert my SCT to hyperstar. And even then I find that Hyperstar doesn’t reduce my exposure time (which is critical due to clouds always rolling in, satellites & airplanes criss-crossing, etc.) by that much. Like, I’m still stuck with 180s and 300s subs in order to get interesting details. I ordered the Optolong L-extreme F2 fast optics filter but it is back-ordered. In the meantime, I's exploring whether a fast triband or a quadband would at least boost the colors…
