[pocketstar]

Not all asteroids are “bright” enough to be imaged from earth, the problem is the low albedo asteroids you cant see, thats why we need this: https://solarsystem.nasa.gov/missions/neo-surveyor/in-depth/

[phkahler]

And even that won't see one on a collision course because there is NO Motion to detect when an object is on collision course.

[bgirard]

Right. If you can't see them, you can't see them. It's not a parallax problem.