Here’s the shot I took with my Canon EOS 50D and EF-S 10-22mm lens with a B+W ND10 ‘Big Stopper’ and a tripod, exposure was 300 seconds at f/22 and ISO400. With so little light left I should have used an ND500 or less instead but then again, if your sensor can handle the exposure time without hot pixels then go for it! Here I had to do some median filter pass on the dark areas, crank up the noise reduction and reduce clarity in those areas to get rid of the pixel noise. I guess I have to look into @leefilters or similar.
Alexander Ipfelkofer 