The Eye in the Death Tar

The dish is a spherical advition that gets light from space and then reflects it back to a single point. It focuses all the light from one ion at one point, and all the light from another direction at a different point. They built this thing in the sixties when everybody was worried about the soviets nooking us. And they were trying to figure out how we could get early warnings of missiles coming in. So using that, you can get a pretty good sample of the sky, because the earth itself is turning.