Yes, I've always focused manually for astrophotography, and it always results in a series test images. Even using the live view at 10x, there is still room for improvement even though it is a good start. It's always a take pic, zoom all the way in on preview, and then make adjustments from there.

I would buy an entire kit if they would release modern glass with 100% manual including aperture. There are places that will rehouse your lens so that it is full manual. The cost pretty much doubles the cost of the lens, but I have been tempted to do that for the 70-200.