w7ay
Hi Chen,
Seems a bit random but maybe related to calibration frames.
I imaged the cat's paw last night and stacked it with version 1.5.6 with no calibration.
![](https://bbs.astronomy-imaging-camera.com/assets/files/2022-06-27/1656308097-784981-image.png)
I did the same with 1.6 and it was fine.
I loaded some bias frames and can recreate the problem, even though bias on their own should do nothing, right?
The stack was ok until I moved a slider, then I pressed Auto.
![](https://bbs.astronomy-imaging-camera.com/assets/files/2022-06-27/1656308352-912798-image.png)
![](https://bbs.astronomy-imaging-camera.com/assets/files/2022-06-27/1656308424-70507-image.png)
I tried to recreate the problem in 1.5.6 by adding bias frames and no matter what I did, it always worked ok.