No knowledge either, but it looks to me like the "noise" is actually made of stars. Maybe you didn't zoom far enough? At sub-maximal zoom, there is aliasing re

No knowledge either, but it looks to me like the "noise" is actually made of stars. Maybe you didn't zoom far enough? At sub-maximal zoom, there is aliasing resulting from a lack of low pass filtering before the resolution reduction. That looks a bit like sensor noise.