ZWO flats

[knobby]

Hi, I have a ZWO 1600 mm pro and the flats look grainy , or could be CMOS pixels ? Aimed for 18000 in APT flats wizard ... Chose 0 gain and 0.5 seconds with 2 white at shirts pointing at blue sky.

Opinions greatfully received.

[souls33k3r]

I'm not sure it would help mate but I've used 30000 +/-500 ADU for my flats  and let SGP calculate the time. I can't remember what it was but I can let you know when I get home. 

[knobby]

Cheers Ahmud, well after stacking 50 flats with 50 dark flats the master flat looks nice and smooth.