A minor detail, but it gave me quite a headache. If a target is not in view, you want to know where it roughly is, right? I've created a target hint that is drawn just outside the telrad circles.

In the picture below, the target is south, below left, and the hint points right at it:

The target hint follows azimuth, altitude and roll. I still have to test how it behaves for targets near the zenith, but I'm too lazy right now.

Special Thanks to the folks in the gamedev.stackexchange chat!