I'm sorry Peter I am not very clear on what your restriction is. And this "just start happening"? Did you recently make an architectural or imaging train change that made this a requirement? It's possible that ACP Expert won't be able to accommodate that unusual of a restriction in the hardware. Can you explain a bit more? If your restriction is around the meridian, it may be possible to have the scheduler avoid starting Plans whose Observations would extend to within some hour angle of the meridian. Can the scope flip safely if started far enough to one side and with it going far enough to the other side?