Stack of 88 two-minute exposures at f4, ISO 1250 on Canon 1Ds. Celestron CGE mount, unguided, no drift alignment. Canon 600mm/4.0L lens, no tele-extender. I rather like how the spiral nature of the galaxy in the bottom left corner shows up, M88. The inset is at 1:1, for the pixel peepers. But note that in Deep Sky Astrophotography you are often peeping at the tracking precision and accuracy of alignment during stacking, rather than the limits of the optics.