This image was taken over three nights from a location near Elk Island park, about 45 minutes east of the city. On the light pollution map it appears as a yellow zone. So, it's not a fully dark site but still, a whole a lot better than my back yard in the city.
At the time, this was my longest run of exposures for a single image. The total exposure time was over 12 hours of which about 7 hours worth was actually useable. The sub-frames are a variety of exposures ranging from 4 to 15 minutes each.
Below is a list of the exact exposure times per filter:
This untidy set of frames was not by design. What actually happened was after each session I would process the images and see how things turned out. Then, for the next session I'd make some changes to see if it would improve things. The end result was a variety of raw frames, all of which contributed to this image.