ASI294MC Pro Flats question

[AndyThilo]

Hi

Does anyone know the 'optimal' exposure time for flats with an ASI294MC Pro? Currently I'm using a Gerd Newmann flat field generator with a 12V -> 3V adjustable regulator. With it set to 4.5V I'm getting 4sec exposures @ ADU 25000. 4 sec is what APT's flat aid. It all seems ok but I'm always looking to improve areas where I can and wonder what others thoughts were?

Thanks
 

Andy

[Laurin Dave]

Hi Andy

I don't know but that ADU looks right..  As do the images you've posted the questions I'd ask are does the master flat you create from them work?  ie does it flatten a flat?  and how are you calibrating the flats? I'd use a matched master flatdark for cmos.  Also if you're not doing it already I'd use dithering as this will help to remove any remaining fixed pattern noise. … 

Dave 

[AndyThilo]

Hi Dave

The flats seem to work fine, just like to know it's right or if there's an optimal exposure time. I take flats and flat darks straight after my lights, same temperature. I stack everything in PI using a modified BPP script which allows flat darks to be used instead of Bias frames. I do dither every frame in APT and also use that to drizzle in PI as my 294/Esprit 80 is a little undersampled. 

Cheers

Andy