Well, I tried to go for some very far and faint objects but they are just too dim for my current gear.
Here is the Crab Nebula. Not much detail (kinda looks like a red thumbprint). Granted, this is a difficult object and I DO actually have some data here. But this represents the current limits of my rig. What are the limits?
This example of the Whirlpool galaxy suffers the same problem. Although not bad (you can easily see the definition of the spiral arms and the companion galaxy), but there is little fine detail and lots of noise.
How to get more exposure time? Ultimately I need a different mount -- an Equatorial mount.
My current Alt-Az fork can aim and track, but not ROTATE with the sky. So I am limited to about 30-45 sec. exposures before I get sky rotation (and blurred stars). Even with stacking, I can't rise enough beyond the ceiling of noise. So, time to find some brighter objects while saving up $$ for a new mount!