ZWO ASI1600MM Pro.
ZWO EFW 8 position wheel with 7, 31mm unmounted filters, purchased as a kit with the ASI1600MM Pro.
Meade 70mm f/5 Quadruplet.
Sharp gradients appear in my flats and lights. I've done a few things to try and understand what is causing them. I have rotated the camera by unscrewing it slightly and took some flats in each filter position. This is to see if the problem is isolated to the camera or something in the rest of the optical train. The sharp gradients appear in all of my flats and do not move in-frame when I rotate the camera independently of the EFW. This suggests that the problem is isolated to the camera itself. To see if the problem is with the sensor, I chose a 900 second dark frame in the ASIAIR Pro. The resulting dark frame showed no hint of the sharp gradient. As a result of this test I am not suspecting an issue with the sensor itself. Now I'm concerned there is an issue with the window in front of the sensor due to the results of my tests. Has anyone experienced this, or anything like it, and if so, what did you do? If this is normal, I've never seen anything this bad.