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,
In my images, I often am challenged by similar results of APP stack and light pollution removal attempts that show in the attachments.
For now this is my equipment:
Canon 5Diii astro modified
Canon 100-400mm f/4.5-5.6L ii
This image of NGC 7822 is at 390mm. 32x300second images.
I just wonder if there is a way in APP to avoid the three rings of brightness. Dark at the borders, a lighter donut, then a darker center. Â
Attachment 1 = Demo_v3a - Stretch to show the issue. Stretch = 10%BG,3sigma,0,0% base, no light pollution removal.
Attachment 2 = Demo_v3b - Stretch to show the issue. Stretch = 10%BG,3sigma,0,0% base, WITH light pollution removal attempt.
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I appreciate any guidance.
Regards,
Andy
Hi Andy,
Do you use flats with APP? If yes, how do you take them? To me it looks like an issue where the flats overcompensate the lights. This is not light pollution.
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Wouter
Thank you. I expect you are correct. I did use flats shot with a light panel. As I am learning AP I think my flats exposure time is too short. Â
On the journey.....
Â
Andy
As a rule the peak of the histogram of the flats should be between 30% and 70%. If your exposure time is too short then the peak will lie to the left of that and you indeed should increase the exposure time.
Wouter
And it probably also depends a bit on how short your exposure was. If it's like 1/1000 of a second, it may also be that the sensor data is not behaving properly. This also is an issue sometimes with bias, take bias at at least 0.05 seconds and flats at around a second(or higher than 0.05) at least. Also make sure that you need to calibrate your flats with bias or darkflats and just once, not twice by accident.
In cases where there is nebulosity everywhere and no obvious areas of dark sky background how do decide where to place the squares?. I am new to APP but have had success with your example of the large magellanic cloud but I downloaded some data to practice on which seemed to be all nebulosity and am at a loss as how to proceed.
Mike Evans
Sorry to have missed your question, in cases like that there aren't many options. I would stretch to the max (30% setting) and up saturation. Then I'd select a few regions where the nebulosity is lowest and see if that works for the overall image.
Thanks, I'll try that
Mike
