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've been following this tutorial..
..I have split the Sulphur, Ha and Oxygen channels. I have three seperate files. Each file was made using the exact same data sets (two sessions worth), using the exact same settings, and yet the Ha channel is askew.
I've tried rotating it 1 degree and it appreas to be good, but when I use rgb combine it looks like a ghost image because the one channel doesn't line up. Everything is just slightly off.
What would cause one channel to not be aligned with thr other two despite containing the same data and processed using the same settings?
I'm kind of at my wits end here. I'd appreciate any help, and I'm sure it's something stupidly easy I'm missing..
Bizarrely I'm not allowed to upload FITS files here (?), so here is my Dropbox containing the files, can someone have a look at it please and see what the deal is?
Dropbox File (Private or Invalid)
I forgot to add that when I take the three channels and try to combine them it says they aren't the same size and it doesn't work. So when I do a batch crop it WILL allow rgb combine to work, but obviously cropping doesn't align the three channels. The Ha channel is still askew.
Is there a way to align everything before I do a batch crop and rgb combine?
@jay6879 Hi,
Just load the integration results as lights (no calibration data), go to tab 4 and register them against each other. That will make APP align the images and give them the same dimensions. You can then save the registered frames at the bottom of tab 4 and load those into combine rgb.
HTH, Wouter
So I would load Ha, OIII and Sulphur as Session 1,2,3 accordingly as lights, and juat register them?
Ok! I'll give that a go tonight, I've spent quite a bit of time trying to figure this out and if this works woo there will be another tool added to my knowledge of APP. I can use this going forward when combining any set of data, just make sure to register them so they are aligned and sized properly. I appreciate the help, I'll let you know how it goes!
Bizarrely I'm not allowed to upload FITS files here (?), so here is my Dropbox containing the files, can someone have a look at it please and see what the deal is?
Sorry for the late reply to this. To the top of every forum page there are upload instructions. We don't allow large uploads to the forum and we have a separate file server for that.
Having said that, I have downloaded your files and will have a look. Do the ones you made available contains the file that you rotated manually?
That did it! Much appreciated. I followed the video and my colors didn't look anything like his, mine were very muted, but that's something I'm sure I can figure out messing with sliders.
..I have split the Sulphur, Ha and Oxygen channels. I have three seperate files. Each file was made using the exact same data sets (two sessions worth), using the exact same settings, and yet the Ha channel is askew.
I had a look at the files that you uploaded. I think a meridian flip was involved when imaging. APP probably selected a light that was taken after the flip as reference and that resulted in an image that is rotated 180º wrt the OIII and SII images. Other than that I see no obvious differences.
Ahhh that makes sense. Is there a way to set what APP uses as the reference frame?
Regardless, it's good to know that you can register the images again and they'll be aligned nicely.
Is there a way to set what APP uses as the reference frame?
Yes there is. After loading the images, go to tab 3 and click "analyse stars". When it is done, go to tab 4 and select the file you want to be reference in the file list. Right click and select "set as reference" et voila!
Why would you want to do this? APP has very good internal algorithms to select the best frame as reference. In general you should not need to do this manually.
