Strong banding on FM150 under 2.5s

[wjdrijfhout]

I just bought a FlatMaster150 and experience very strong banding. See here a stack of 25 flats at 0.1s (Luminance filter, brightness setting 50):

Banding.jpg (1.82 MiB) Viewed 24488 times

At 1s banding is less and will calibrate out during stacking most of the time. Only at 2.5s flats are free of banding.

Is this normal?

I'm aware that in the old times, LED panels were using relatively slow PWM to adjust brightness, and the slow switching could give this banding. But I thought that nowadays PWM techniques have improved a lot and use much higher frequencies, making exposures in the range of 0.1s easily possible?

Yes, I need to clean my filters too....

[rodolgo]

Hi
Same issue here - the solution is I believe, to increase the shot duration, at least to 3 seconds or more.
You can play with the brightness to achieve this for LRGB filters - it also depends on your scope aperture.