ok I’ve now got an led flat panel by the magic of Amazon.
I tried the auto flats option in ekos which came up with an exposure around 0.6 sec and also manually using aperture priority which gave 0.07 secs. Both came out with pretty similar distributions of pixel levels.

I still had first exposure out of the 10 or so I did hit 16384, the rest seemed fine.

The interesting/learning thing was that I used AstroImageJ to inspect the images using a 3d plot and found that my old flats where over exposed in the middle. You could see the dent of it hitting the limit in the middle of the dome of the vignetting. The new ones were a nice smooth dome which didn’t get flattened by hitting the limit. Expect that will make a difference to the final images.

Read More...