MAY 4 2026: APP 2.0.0-beta44 has been released !
New improved internal memory controls should now work on all computers
May 1 2026: APP 2.0.0-beta43 has been released !
Improved internal memory controls (much more stable and faster on big datasets), fixed CPU image viewer, fixed Narrowband extraction demosaic algortihms.
Apr 29 2026 APP 2.0.0-beta42 has been released !
New improved Normalization engine, Fixed random crashes in integration, fixed RGB Combine & Calibrate Star Colors, fixed Narrowband extraction algorithms, new development platform with performance gains, bug fixes in the tools, etc...
Apr 14 2026: Google Pay, Apple Pay & WeChat Pay added as payment options
Update on the 2.0.0 release & the full manual
We are getting close to the 2.0.0 stable release and the full manual. The manual will soon become available on the website and also in PDF format. Both versions will be identical and once released, will start to follow the APP release cycle and thus will stay up-to-date to the latest APP version.
Once 2.0.0 is released, the price for APP will increase. Owner's license holders will not need to pay an upgrade fee to use 2.0.0, neither do Renter's license holders.
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
