UPDATE FROM MABULA
I have had a very rough 2 months unfortunately health wise. I was struck 3x in a row with bacterial infections. The second infection occurred  after a routine hospital checkup and I became very sick. I had to rest and take a lot of antibiotics. Once I was recovering and restarting work 1 month ago, I again became sick. The infection was not yet gone, so even more antibiotics and rest was needed. Needless to say, it took a lot of my energy and I needed a lot of rest.
Finally, the infection is really gone and my energy is coming back step-by-step now and I have started work again. I am terribly sorry to have kept you waiting for support. I will address all outstanding questions and e-mails step-by step and will be on the forum daily from today.
APP 2.0.0-beta47 will come soon as well, a lot of work was already completed before I became very ill, so the release is also nearly ready for you. Beta47 will be much faster actually. Many workflows will be more than 2x faster, mosaics can even be 10x faster than before because registration really received a major boost... all compared to beta46. Â Before I release it, I will make sure that everything is working properly and then I will release it.
Hello, I'm trying to figure out if I'm doing something wrong or if it's a software bug.
Basically I'm trying to work with ONLY flat frames and lights with my Sony a6300.
If I create a 32 bit MasterFlat it overcorrects the lights. I'm trying to do a 4 panel mosaic so I need my lights to be flat calibrated correctly.
Interestingly if I calibrate some Lights manually in Photoshop using the exact same flats they correct perfectly, although I don't want to calibrate 250 Lights by hand...
So I tried to use 16 bit MasterFlat because this helped me in the past with my a6000 and as you can see it does not look overcorrected around the corners anymore.
But now there's a very weird pink purple circle in the middle of the frame. APP also saves the files like this and the finished integration also looks quite similar.
Maybe someone else has an idea. Thanks
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Some data:
Samyang 18mm f2.8
Sony a6300 ARW raw data
lights 60sec iso400 f2.8
flats 0,005sec iso400 f2.8 (which has never been an issue in the past)
I use a Lacerta dimmable flat panel
latest Beta of APP, earlier 2.0 versions - same behaviour
older 1.8.x versions overcorrect even MUCH worse, no matter if 16 or 32 bit masters
latest gpu drivers and everything
pls help me I'm under the water. thank you
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*UPDATE*
I took some fresh BIAS frames and 32 bit calibration does work now
Okay just tested 16 bit which is also working!
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What do we learn from this?
USE BIAS OR DIE lol
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(I leave this here should anybody else experience this issue, should this be a problem feel free to delete it)
haha Indeed, flats always need to be calibrated with a bias or DarkFlat as APP won't otherwise know what the background signal is.
In the past I got something very similar to this. Mostly if I was calibrating with flat files. But the circle remained (but very very faint) even if I was integration with bias&darks or without calibration frames at all.
After month dealing with this issue while post-processing and searching for a solution, I realised that i accidentally activated an camera option "shadow correction", which in day time images removes most vignetting effect (but obviously failes on astroimages). This correction is even saved to raw files, so no removal afterwards. After deactivating this, the circle was gone, everything fine now.
Hi Robert,
I am glad the issue is already solved, but i think we can give you a better explanation here as well why bias/dark/darkflats are essential to get the best flat calibration possible.
Any sensor will have a base offset from which it starts recording the incoming photons. For most camera's and thus sensors in camera's, this base offset is not zero = 0. If it would be zero, than you would not run into your problem. If the base offset is 500 ADU, that base ADU will be in both your lights and flats. We need to subtract that base level first before the flat field calibration can work like expected 😉
darks/bias/darkflats will do this subtraction of that base level 😉 because their signals will be created from that base level, in case of darks, the signal will be slightly higher than the base level because of dark current build-up like in your lights.
Hope this clarifies it 😉
Mabula
