Mar 28 2026 APP 2.0.0-beta40 will be released in 7 days.
It did take a long time to have the work finished on this and it will have a major performance boost of 30-50% over 2.0.0-beta39 from calibration to integration. We extensively optimized many critical parts of APP. All has been tested to guarantee correct optimizations. Drizzle and image resampling is much faster for instance, those modules have been completely rewritten. Much less memory usage. LNC 2.0 will be released which works much better and faster than LNC in it's current state. And more, all will be added to the release notes in the coming weeks...
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 everybody !
First of all, I would like to precise I'm a beginner in all of this : stack, DOF, etc. But I've read a lot, and I think I'm rather aware of basic concepts. I'm shooting with a D850 unmodded, with a Tamron 35mm f1.4 @ f2 ; 2min ; ISO 400 for this example.
I'm facing a problem, and I cannot find its origin. After Light pollution removal, I have a kind of ring in my picture. And I cannot remove it. It's "subtle" but increasing with further post processing. Here with a huge stretch.
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It may come from the flat, so I did a loooot of tests : expose to the left, to the right, centered, on the sky, using a teeshirt, high ISO, low ISO, fast flat, low flats... I used 1, 15 and 30 flats to calibrate. With other post-processing software, the same occurs. I try to stack uncalibrated raw files, and the ring seems to be here as well.
I've read this : https://www.cloudynights.com/topic/557931-concentric-coloured-rings-caused-by-flats/ ; and this https://www.cloudynights.com/topic/746131-nikon-coloured-concentric-rings/ but not sure if related.
Or, maybe I'm not good at using light pollution removal tools. Or I failed, each time, doing proper flats. I'm currently stack an other object, with another lens (90mm), from another place... I will see if I observe the same, to check if it comes from my camera.
Do you have other ideas of what I could check ? Here is a flat, a bias and a light (no dark as I was at ISO 400 and my sensor's camera is really powerfull) : https://drive.google.com/drive/folders/18fy2jwC3ae0Q8flq5YwJShjmV2Pe8crl?usp=sharing
It's the first time I ask on a forum a solution, normally I always find it by myself. 😓Â
PS : just an idea by writing, the focal could be the problem ? 35mm on a full frame sensor is quite wide.
@thibautflt That is quite a challenge, yes. Could you post the unprocessed stacked file as well? Also, what exposure time do you use for the flats?
Thank you for your answer. I've added some fits files from my tests in the previous folder, you can look this one : https://drive.google.com/file/d/1Q6OdIKus0oWtDiYEntLXfNXTswPbl_U2/view?usp=sharing
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Forgot to mention that I've tried both electronic and mecanic shutter to do my flats, no changes. And I have flats with 3s exposure, others with 1/8000s. They produce more or less the same result.
@thibautflt Many thanks for that. Indeed the ring is difficult to get rid of. I started with saturating the colors to an extreme and then with placing a few small boxes along the edges of the image and then slowly added more and more boxes in both the darkest and the lightest areas with no emission nebulae and managed to suppress the ring quite a bit.
Then I cropped the image and reset the saturation. Then I upped the saturation again a bit to bring out the colors of the nebulae and this is what I get:
What happens if you integrate the lights without flats and only use darks?
@wvreeven your result is far better than mine !
In the folder here : https://drive.google.com/drive/folders/18fy2jwC3ae0Q8flq5YwJShjmV2Pe8crl there is a .fits file "M42_region_noDOF.fits" I obtained stacking light frames without calibration. It is not clear for me but the ring seems to be here... what do you think ?
I'm going to redo the integration, using only darks as you suggested.
