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.
Hi all,
Because of a software error in the telescope setup, during a meridian flip half of my images ended up being mirrored and flipper per se when a meridian flip occurred; and so they failed registration. I tried to deal with this by making the following changes to the Registration step:
- Checked 'flip x/y'.
- Unchecked 'same camera and optics'
- Changed the registration from 'quadrilaterals' to 'triangles'
Now registration succeeds, but then I get a series of errors in Normalization, like this:
Just to see what was happening, I temporarily disabled normalization, and after RGB combine, this is what my image looks like:
(The individual channel files look pretty much like that too. I suspect that normalization is failing when trying to normalize the leftover margin areas after registration.
Any suggestions for how to deal with this, so normalization succeeds? (My thought was to save the registered frames, then bulk crop them, then resume integration with the cropped frames – but I’m not exactly sure how to do that, or if that’s even the correct approach.)
It’s also possible that my approach for handling the mirrored subs in Registration is not correct.
Thanks,
Charles
Mmm, I think it's best for us to have a look at the data. Would you mind uploading a small subset of your data? Like 10 lights, 10 darks, etc. ?
I have uploaded 6 files each of LRGB to folder "cdp17-registration". They are all light files (already calibrated by iTelescope before being delivered to me).
BTW the version I am running is 1.083.4, which I believe is the latest.
I appreciate you looking into this!
Charles
Ah, precalibrated. Mmm, if I'm right iTelescope also provides the calibration files seperately and raw lights. I think it will be very informative if you can get those and upload as well as this may very well be a calibration issue. This is better anyway as APP will have better calibration algorithms to use.
Hi Vincent,
I will try to get the raw lights and calibration files (I hope the raw files haven't been removed from the iTelescope FTP site yet), but it may take a few days.
In the meantime, I do see something suspicious in APP. If I examine these files with an external FITS viewer (AvisFV), all of the files look normal, except that the "W" images (after meridian flip) are mirrored:
However, inside APP, with the image viewer the "E" images look normal, and as they do in AvisFX; but every one of the "W" images has a histogram that does not look right, and the image is all wrong (it's supposed to be monochrome, for one thing):
I am not experienced enough to know whether this indicates image issues or an APP issue, but I thought I'd bring it up as a data point.
Thanks again,
Charles
The external application shows a very stretched result, it's not possible to judge what is going on in the background there. Also if they are mono, then it seems the data has a wrong header tag maybe, does it show an RGB pattern in the fits header?
Anyway, when you have the data, please let me know and we can probably tell you what is going on. For now this does look like a data issue.
Hi Vincent,
Thanks to the excellent iTelescope support staff, the issue is resolved. In a nutshell:
- Software bug on telescope system introduced a spurious “BAYERPAT” line in the FITS header after a meridian flip.
- This line made APP believe that the camera has a Bayer mask when in fact it does not; hence the incorrect image viewer/histogram, and the failure to integrate.
- Two workarounds were successful:
- Use current version of APP with “no interpolation” on tab 0
- Use older version of APP (1.078) which (apparently) does not pay attention to the BAYPERPAT line in the header
The idea that the incorrect BAYPERPAT line fooled APP is just a working theory, but in conforms with the workaround results. In any case, this should not happen again since the iTelescope team has corrected the processing error on the telescope system.
I very much appreciate for your offer to help, but I’m glad I did not waste your time on what in fact turned out to be an image issue – as you suspected from the start.
Cordially yours,
Charles
Thanks for coming back to explain what happened Charles! That is very helpful. Glad it's figured out.
The BAYERPAT line indeed fooled APP as it does expect that tag to be correct. This was indeed introduced in a later version.
@cdp17 There is a third option: remove the BAYERPAT FITS keyword from the raw files. This is possible via the tools in the Tools tab of APP.
Wouter, thank you for drawing my attention to that feature - I wasn't aware of it!
Charles
