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 Mabula,
I have been reading your draft 1.076 release notes: in particular the last section dealing with Star Analysis Quality. I have never previously fully understood how quality was calculated so I was hoping for enlightenment but have to say I am still somewhat unclear about the calculation?
You state that 'The star size and roundness are based on the median star profile of all stars analysed'. Does this mean the median of all the stars in all frames currently selected? Or is the median calculated for all the currently selected frames for a specific filter and/or session?
I am probably missing something but it also seems to me that for a given set of frames the median star size and median star roundness will be constants. So to me this is saying that the quality value is thus proportional only to the number of stars? In determining 'quality' I am thinking that there should be something to compare the median star size and roundness of a particular frame with the corresponding median values of all the stars in the overall population of frames, i.e. a frame with smaller and rounder stars than average should score higher than a frame of average or below average values. If you agree this is relevant I am not seeing how it is being taken into account?
Despite these questions I have been using APP for some 2 years now and still think it is a great product and I am very much looking forward to the next release.
Best Regards
Mike
Hi Mike @mestutters,
You state that 'The star size and roundness are based on the median star profile of all stars analysed'. Does this mean the median of all the stars in all frames currently selected? Or is the median calculated for all the currently selected frames for a specific filter and/or session?
This is quality calculation for each frame individually, so of a single frame, the median star profile is found. The star size and shape of that star profile determines the score. The frame quality after star analysis is a combination of both the size and roundness of the star multiplied by the number of stars.
I am probably missing something but it also seems to me that for a given set of frames the median star size and median star roundness will be constants. So to me this is saying that the quality value is thus proportional only to the number of stars?
Indeed, that interpretation is not correct. In a single frame we can find let's say 250 stars. Of those 250 stars, we find the median star profile, because that is not sensitive to bad detections (like a small galaxy) and outliers in the starlist. The median profile therefor is a very good indication of the star quality in the entiry frame.
In determining 'quality' I am thinking that there should be something to compare the median star size and roundness of a particular frame with the corresponding median values of all the stars in the overall population of frames, i.e. a frame with smaller and rounder stars than average should score higher than a frame of average or below average values. If you agree this is relevant I am not seeing how it is being taken into account?
So for each frame we calculate this star size and roundness of the median profile and multiply it by the amount of detected stars. Those frame scores are calculated per frame. So after star analysis, these scores still don't say a lot because no check has been made relative to the other frames, right?
After registration, the relative FWHM min, max, shape are calculated based on the registration parameters between the frames. If there are image scale differences (due to different camera/OTA, focal length etc) in the dataset, the scores are now corrected properly.
Your suggestion
something to compare the median star size and roundness of a particular frame with the corresponding median values of all the stars in the overall population of frames, i.e. a frame with smaller and rounder stars than average should score higher than a frame of average or below average values.
is not enough when you process data of different optical setups at the same time so the registration engine corrects for the quality scores found after star analysis ;-).
The smaller and rounder the stars, the better off course. The higher the star density, the better off course. The star density is also the correction for the absolute star count after registration.
I hope this clarifies this more ?
In the soon to be released documentation all will be explained in detail 😉
Kind regards,
Mabula
Hi Mabula,
Thanks for the detailed reply. That is in line with what I thought should be happening. For clarity might I suggest you append the words underlined to this sentence in your release notes.Â
The star size and roundness are based on the median star profile of all stars analysed within each frame.Â
I am looking forward to the release of v1.076.
Regards
Mike
