I used Batch Preprocess script with 30 x 1 minute subs, 30 bias , 30 darks and 30 flats. Imaged with Canon T3i from very light polluted area, just for testing.
Flats were shot with white T-shrt and dawn sky with 1/6 th shuter speed. I switched to Av mode and let the camera decide the shutter speed with histogram in the middle.
Then i switched to Manual and continuously shot the rest of the Flats with the same settings.
Now i can't rid of that persistent large dust mote as you can see on the image. In the bottom i opened Calibrated light frame and the mote is barely seen, i have to move my head around the screen to notice some resemblance of it. But when Integrated it's very strong. Also the Vignetting corrected in some weird way, my flats and all 4 of the corners were vignetted, but on the stack it seems that only right side were corrected.
I got that result with the BP script, but then tried and Integrated Lights my self with the recommended settings.
Is clear that my Lights wasn't Calibrated with flats? Do i have bad flats or settings?