I've been at this hobby for almost 20 years now, but tonight marks a milestone in data capture.  Tonight, I combined all the data over the last 4 years of Messier 51 (the Whirlpool Galaxy) into a single image.  This data was captured start in 2015, and consisted of 10 minute exposures.  This year I started capturing 20 minute exposures with the same mount, telescope and camera.

Here is the result:

Full capture details & clickable large image available here