Bright patch on image.

[Shaun_Astro]

I took some more subs of m31 last night. The moon was over 90 deg away, yet the stacked image shows a glaring gradient swamping half the image, is this the moon? I've not seen anything like it. I think it might be the SW 0.9 CC perhaps. Since I have used it my flats never seem to work properly. 

I'll add an image once back from work..

Edited November 8, 2019 by Shaun_Astro