On the left, an 210 sec light polluted image and on the right 7 of the same 210 sec images stacked with equal darks, cropped in PS and processed in PS including a star mask to make diffraction spikes. Taken at 800 ISO on Canon 70D through the 80 mm Equinox refractor in July 2016. Of note, how the PS processing takes out the light pollution and improves the image!