found a 40D focusing tip

At last, I found a handy tip over at the New Forest Observatory blog for focusing with the Canon 40D. Hook the camera up to a computer, use Live View, and zoom in 10 times. Much easier than using the small on-board LCD on the back of the camera, which—invariably—you can't easily see in part due to crazy back-breaking angles. This makes for a strong case for using the computer instead of an intervalometer.