>>3727331oh, smoke haze will fuck astro for weeks. down under in melbourne the fires at the start of the year fucked astro for 3 months afterwards.
they do but to an extent. make sure you're looking up and comparng visible spectrum photos of m31 --- a huge amount of detail is outside visible spectrum.
i don't understand why your 10s sub is so noisy and yucky. attached is just a dumb point-at-sky-and-expose 5s iso 400 56mm@f/1.8