17-40/4L lens set to 17mm and F/5.6. A stack of 20 exposures, each 60s (20min total exposure at iso800). See also here.
A single 8 minute iso800 exposure of Cassiopeia through a Canon 17-40/4L lens at 17mm and F/5.6. The Andromeda galaxy (M31) is visible at the bottom center.
From the same night as my earlier Cygnus photo. This one is not as good with some light pollution or dew-problems at the left. The red artifact in the lower right corner is the same amplifier noise that's visible in the cygnus photo. My home-made lens hood causes vignetting.